CYTOGENETIC EXAMINATIONS IN THE HEALTH CARE SYSTEM: THEIR POTENTIAL ROLE IN PREVENTION OF DISEASES

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1 Cytogenetic examinations in the health care system: their potential role in prevention of diseases CYTOGENETIC EXAMINATIONS IN THE HEALTH CARE SYSTEM: THEIR POTENTIAL ROLE IN PREVENTION OF DISEASES Badania cytogenetyczne w aspekcie klinicznym w ochronie zdrowia. Potencjalne znaczenie profilaktyczne Agnieszka Stembalska, Ryszard Ślęzak, Robert Śmigiel, Maria Małgorzata Sąsiadek* Wroclaw Medical University Abstract Chromosomal aberrations belongs to the group of the most frequent causes of infertility, congenital defects, mental retardation, and sex determination disorders. Identification of numerical and structural chromosome aberrations allows for pre- and postnatal diagnosis and thus for genetic counseling focused both on the patient and the patient s family. The present paper discusses the importance of cytogenetic examinations in the diagnosis and management of 1) infertility and reproductive failure, 2) fetal defects (prenatal diagnosis), 3) congenital defects and mental retardation syndromes, as well as 4) the methodological foundation of laboratory cytogenetic diagnosis. Keywords: cytogenetic studies, karyotype, infertility, miscarriage, prenatal diagnosis, congenital defects Słowa kluczowe: badania cytogenetyczne, kariotyp, niepłodność, poronienia, badania prenatalne, wady wrodzone Introduction With advances in medical knowledge, genetics, and molecular biology, it has become clear that a large proportion of human diseases are linked to genetic alterations. Apart from diseases with purely genetic etiology, such as chromosomal aberration syndromes and conditions due to single gene mutations, many disorders are caused by a combination of genetic and environmental factors, such as arterial hypertension and diabetes. There are also a number of conditions that are almost entirely caused by external factors, such as congenital cytomegalovirus infection or trauma. Genetic diseases may result from a change (aberration) in the number and/or structure of chromosomes, mutations in single genes, or defects involving many genes and detrimental external factors. Chromosomal aberrations are most frequently manifested by clinical symptoms such as dysmorphic features, congenital defects, and impaired sexual, motor or intellectual development. In clinical practice, a frequently used term is chromosomal phenotype, which suggests a known or undetermined chromosomal rearrangement as etiological factor. The identification of chromosomal aberrations in a patient enables physician to make a diagnosis and probable prognosis, and to determine further diagnostic, therapeutic, and rehabilitation procedures. It also serves as the basis for offering genetic advice to the patient and his or her family. This also includes pre-conception counseling and evaluation of the risk of recurrence of the same disorder, as well as prenatal consultations. Thus, cytogenetic tests constitute an element of: First-line prevention of chromosomal aberrations, mostly through in vitro fertilization with preimplantation genetic diagnosis; Second-line prevention early diagnosis of chromosomal aberrations enables implementation of optimum further diagnostic procedures and thus therapeutic management; * All authors equally contributed to the paper. Journal of Health Policy, Insurance and Management Polityka Zdrowotna 37

2 Agnieszka Stembalska, Ryszard Ślęzak, Robert Śmigiel, Maria Małgorzata Sąsiadek Third-line prevention (early support, physical therapy, etc.) early diagnosis, treatment, or physical therapy makes it possible to prevent complications linked to existing disorders. Due to the fact that the clinical consequences of chromosomal aberrations may emerge at any time of life, this paper adopts the following chronology of the presented issues: 1) infertility and reproductive failure; 2) defects due to chromosomal aberrations during prenatal development; 3) defects in newborns and children; 4) concise information about cytogenetic testing methods. Cytogenetic tests in couples WIth reproductive failure Reproductive failure, which constitutes a serious problem in contemporary gynecology, may be caused by conception and/or pregnancy failure. Chromosomal aberrations (changes in the number and/or structure of chromosomes) constitute one of the most frequent factor impairing conception (also assisted conception), leading to early or late spontaneous abortions, and causing congenital disorders. Indications for cytogenetic testing of both partners include failure to conceive (also in the case of in vitro fertilization), two or more spontaneous abortions, or giving birth to a child with congenital defects. In this group of patients, the most frequent chromosomal changes do not involve a loss or/and addition of chromosome fragments, but are balanced and include reciprocal chromosomal translocations, including Robertsonian translocations and chromosomal inversions,. Carriers of balanced chromosomal aberrations are healthy, but they may transfer an unbalanced aberration to their offspring. This risk depends on the course of meiosis, including crossing over, and the survival rate of fetuses with an unbalanced karyotype. Knowledge of the mechanisms of such chromosomal aberrations forms the basis for evaluation of the risk of miscarriage or congenital disorders in the fetus. 1 If a person is diagnosed as a carrier of a balanced chromosomal translocation, a pedigree analysis should be done an thus probable carriers of balanced translocation should be identified. Evaluation of the risk of giving birth to a child with an unbalanced aberration, or the risk of miscarriage or fetal death/ still birth in the next pregnancy is conducted on the basis of pedigree analysis using direct methods (only in families where many relatives have been diagnosed as carriers) or indirect methods (grouping of pedigrees of families in which unbalanced translocations appeared in respect of the same chromosomal break-point localization). To assess risk by the indirect method, one needs to have access to databases containing information on families with chromosomal translocations. The Polish Collection of Reciprocal Chromosomal Translocations is maintained by the Genetics Department, Medical University of Białystok. Detecting an aberration in one of the parents is an indication for conducting invasive prenatal tests in each pregnancy. Some patients may consider in vitro fertilization with preimplantation genetic diagnosis. This method allows for determining the karyotype of the embryo even prior to implanting it in the uterus. Examination of a single cell from a blastocyst (usually one cell is taken from an 8- or 16-cell blastocyst) allows for choosing embryos with normal karyotype (normal set of chromosomes). This procedure lies within first-line prevention (prevention of chromosomal aberrations in the fetus). Preimplantation cytogenetic tests are most often carried out using in situ fluorescence (FISH) or comparative genomic hybridization (CGH). 2 1 Sąsiadek M M, Haus O, Łukasik-Majchrowska M, Ślęzak R, Paprocka-Borowicz M, Busza H, Plewa R, Bułło A, Jagielski J. Badania cytogenetyczne u małżeństw z poronieniami samoistnymi. Ginekologia Polska (5a). 1997: ; Pasińska M, Haus O, Skonieczka K, Ślęzak R, Midro AT, Stasiewicz-Jarocka B, Szczepaniak M, Adamczak R, Marcinkowska A, Bartusiak K. Wyniki badań cytogenetycznych i molekularnych u 35 par z niepłodnością pierwotną. Wiadomości Lekarskie (1-2). 2006: Le Caignec C, Spits C, Sermon K, De Rycke M, Thienpont B, Debrock S, Staessen C, Moreau Y, Fryns J P, Van Steirteghem A, Liebaers I, Vermeesch J R. Single-cell chromosomal imbalances detection by array CGH. Nucleic Acids Res (e68). 2006: 34; Schoolcraft WB, Katz-Jaffe MG, Stevens J, Rawlins M, Munne S. Preimplantation aneuploidy testing for infertile patients of advanced maternal age: a randomized prospective trial. Fertility and Sterility (92). 2009: Nr XII/II

3 Cytogenetic examinations in the healthcare system: their potential role in prevention of diseases 1.1. Cytogenetic examinations in fetal loss. Miscarriages are most often caused by numerical chromosomal aberrations, arising de novo. Chromosomal changes are found in 50%- 60% of early and in about 10% of late fetal losses. 3 It is thought that most miscarriages before the 10 th week of pregnancy are linked to non-inherited numerical chromosomal aberrations which arise as a result of chromosome nondisjunction (non-separation) in male or female gametes. In such cases trisomy of chromosomes 13, 16, 18, 21, 22, and X or monosomy of chromosome X are most frequent. The trisomy are usually lethal. Among them trisomy of chromosomes 16 and 22 most frequently observed, while fetuses with trisomy 13, 18, and 21 are sometimes born alive. Cytogenetic examinations of pregnancy lost samples are now conducted by molecular cytogenetic methods, and especially FISH and CGH. They enable fast and reliable determination of a numerical chromosomal aberration, confirming or ruling out such an aberration as the cause of the miscarriage. They also make it possible to prepare reliable genetic counseling for parents including an information what should be done to establish risk of recurrence of an aberration in the next pregnancy and plan for an adequate pre-conception and prenatal diagnostics Cytogenetic examinations in primary infertility Numerical chromosomal aberrations are found only in a minority (7-10%) of couples presenting at genetic clinics due to reproductive failure. These cases usually include males with previously undiagnosed Klinefelter syndrome and females with trisomy X. If a cytogenetic test reveals additional chromosomes X in a male, this usually implies azoospermia. However, in some of these patients spermatogenesis may be partially preserved, which allows for extraction of reproductive cells (spermatids, spermatocytes, or sperm cells) from the testicle and use them for in vitro fertilization. Other causes of spermatogenesis disorders, including azoospermia, are balanced aberrations between chromosome Y and autosomal chromosomes or between some autosomes (mostly acrocentric chromosomes). The presence of an additional chromosome X in the female karyotype usually does not obviously lead to phenotypic defects, but is often linked to the risk of premature ovarian failure. Therefore, detection of trisomy X provides the female patient with important information concerning a potential procreation disorder Cytogenetic diagnostics in sex determination and differentiation disorders The most frequent causes of sex determination disorders in women are structural and/ or numerical aberrations of chromosomes X leading to Turner syndrome (TS). In about 60% of TS cases monosomy of chromosome X, in 5% mosaicism with the presence of additional cell lines containing a different sex chromosome, and in the other cases structural aberrations of chromosome X are observed. In TS patients the age at which the patient is diagnosed is of critical importance for the final outcome of treatment. Analysis of the age of women diagnosed with TS shows that several years ago diagnoses were most often made at age on the basis of the absence of menarche and characteristic dysmorfic features. Today, such a diagnosis is usually made for patients at about 3-4 years of age, presenting developmental delay (a height below 3 centile), thus allowing for early therapy. The key to success in treating most of dysmorfic features, including short stature in TS girls is an early treatment with growth hormone (prior to closure of epiphyseal cartilage) preventing short stature and introduction of estrogen-gestagen replacement therapy. Otherwise, dysmorfic features of TS may pose a problem in social relations and lead to lower self-esteem of the patients (psychosocial consequences). 6 3 Lebedev I. Mosaic aneuploidy in early fetal losses, Cytogenetics and Genome Research (133). 2011: Dutta U R, Rajitha P, Pidugu V K, Dalal A B. Cytogenetic abnormalities in 1162 couples with recurrent miscarriages in Southern region of India: report and review. J Assist Reprod Genet (28). 2011: ; Branch D W, Gibson M, Silver R M. Recurrent miscarriage. New England Journal of Medicine (363). 2010: Otter M, Schrander-Stumpel C, Curfs L. Triple X syndrome: A review of the literature. European Journal of Human Genetics (18). 2010: Ślęzak R. Propozycje postępowania diagnostycznego w zespole Turnera. Biuletyn Informacyjny Komisji Genetycznej Człowieka (7). 2001: Ślęzak R, Sąsiadek M, Dobosz T, Gogulska L, Jagielski J. Oznaczanie swoistych sekwencji chromosomu Y w zespole Turnera. Ginekologia Polska (9). 1999: Journal of Health Policy, Insurance and Management Polityka Zdrowotna 39

4 Agnieszka Stembalska, Ryszard Ślęzak, Robert Śmigiel, Maria Małgorzata Sąsiadek Moreover, an early diagnosis of TS makes it possible to initiate wide-ranging preventive and curative management, including treatment of congenital anomaly linked to TS, and especially malformation of the urinary tract (often asymptomatic), cardiovascular system, and hypothyroidism. An important aspect of preventive management in TS patients is exclusion of the presence of Y chromosome sequences which, under the circumstances, are related to increased risk of cancer of dysplastic gonads. 7 Early gonadectomy may prevent development of gonadoblastoma or dysgerminoma. Anti-cancer prevention is used in every case where the patient s phenotype is female and a cytogenetic test has revealed the presence of chromosome Y, as well as in pure and mixed gonadal dysgenesis, and insensitivity to androgens. Cytogenetic examinations constitute a very important tool in differential diagnostics in cases of alterations in external genitals in newborns (especially in the case of ambiguous genitalia). Suspected adrenal hyperplasia syndrome and virilizing tumors require, along with hormonal, biochemical, and molecular tests, prompt cytogenetic diagnostics for determining the newborn s chromosomal sex. This is necessary for entering the right sex in the birth certificate and also for making the parents aware of the need to conduct plastic surgery of external sex organs in the child. 8 Cytogenetic examinations in prenatal diagnostics Prenatal cytogenetic examinations are part of second-line prevention, that is, they are aimed at early detection (before birth, and often before the third trimester of gestation) of genetic disorders. Thus, the pregnant woman may be given an adequate health care, including intrauterine fetus therapy (treating or reducing the effects of the diagnosed defect, if possible) and appropriate specialized care for newborn (in some cases palliative care). 9 If serious and irreversible defects in the fetus are diagnosed, the parents may also decide to terminate the pregnancy. 10 The frequency of chromosomal aberrations at the time of conception amounts to as much as 40%, but over the course of pregnancy the number of fetuses with chromosomal aberrations decreases due to the high rate of spontaneous abortions. Thus, such aberrations occur in only about 0.5% of newborns. 11 All methods of collecting cells from the fetus are fraught with a risk of complications, mostly miscarriage (about 1% in amniocentesis and chorionic villus sampling and about 2% in cordocentesis). 12 Therefore, such tests should be offered only in the case of medical indications, such as: 13 Woman,s age at conception over 35 years (or >40 according to the Polish Gynecological Society, 2009) due to increased risk of trisomy 13, 18, or 21 in the offspring; 7 Baka-Ostrowska M. Noworodek z obojnaczymi narządami płciowymi. Przegląd Chirurgii Dziecięcej (4). 2009: Stembalska A, Łaczmańska I, Dudarewicz L. Nieinwazyjne badania prenatalne w diagnostyce aneuploidii chromosomów 13, 18 i 21 aspekty teoretyczne i praktyczne. Ginekologia Polska (2). 2011: ; Dangel T. Wady letalne u noworodków, opieka paliatywna jako alternatywa wobec aborcji i uporczywej terapii. Standardy Medycyny (9). 2007: ; Pergament E. First-Trimester Genetic Counseling: Perspectives and Considerations. Clinics in Laboratory Medicine (30). 2010: ; Sharma G, McCullough L B, Chervenak FA. Ethical considerations of early (first vs. second trimester) risk assessment disclosure for trisomy 21 and patient choice in screening versus diagnostic testing. American Journal of Medical Genetetics Part C Seminars in Medical Genetetics (145C). 2007: Ustawa o planowaniu rodziny, ochronie płodu ludzkiego i warunkach dopuszczalności przerywania ciąży z dnia 7 stycznia 1993 r. (z 1993 r., Dz.U. Nr 17, poz. 78; z 1995 r., Nr 66, poz. 334, z 1996 r., Nr 139, poz. 646, z 1997 r. Nr 141, poz. 943, Nr 157, poz i z 1999 r. Nr 5, poz. 32). 10 Branch D W, Gibson M, Silver R M. Op. cit.; Lebedev I. Mosaic aneuploidy in early fetal losses, Cytogenetics and Genome Research (133), 2011; Zhang L, Zhang X-H, Linag M Y, Ren M H. Prenatal cytogenetic study of 2782 cases of high-risk pregnant women. Chinese Medical Journal (123). 2010: Stembalska A, Łaczmańska I, Dudarewicz L. Op. cit.; Ball R H. Invasive fetal testing. Current Opinion in Obstetrics and Gynecology (16). 2004: Stembalska A, Łaczmańska I, Dudarewicz L. Op. cit.; Stembalska A, Ślęzak R, Pesz K, Gil J, Sąsiadek M M. Prenatal diagnosis - principles of diagnostic procedures and genetic counseling. Folia Histochemica et Cytobiologica (45) Supplement : 11-16; Stembalska A, Ślęzak R, Sąsiadek M. Badania prenatalne. Family Medicine and Primary Care Review (1). 2005: 18-24; Ślęzak R, Florjański J, Zalewski J, Sąsiadek M, Heimrath J. Diagnostyka prenatalna triploidii. Ginekologia Polska (4). 2005: ; Anderson C L, Brown C L. Fetal chromosomal abnormalities: Antenatal screening and diagnosis (79). AFP 2009: ; Gil J, Pesz K, Sąsiadek M M, Stembalska A, Ślęzak R. Genetyczna diagnostyka prenatalna, metody badań, elementy poradnictwa genetycznego. Badania Diagnostyczne (7-8). 2008: Rekomendacje Polskiego Towarzystwa Ginekologicznego dotyczące postępowania w zakresie diagnostyki prenatalnej. Opracowanie zespołu ekspertów. Ginekologia Polska (80), 2009: Nr XII/II

5 Cytogenetic examinations in the healthcare system: their potential role in prevention of diseases numerical or structural chromosomal aberration in previous fetuses or children; congenital defects that may have been caused by chromosomal aberrations found in previous fetuses or children (whether stillborn or live born); either of the partners is a carrier of a clinically significant balanced chromosomal aberration, because this increases the risk of having offspring with an unbalanced karyotype; abnormal results of non-invasive prenatal examinations (ultrasound) and/or biochemical screening tests, giving rise to a suspicion of chromosomal aberration in the fetus. Women who meet at least one of the above indications for a cytogenetic examination of the fetus belong to a high risk group in terms of giving birth to a child with congenital disorders and fall under the Prenatal Testing Program in Poland. 14 Genetic prenatal counseling is non-directive, and is only of informative nature (explaining, completing, and verifying data). The final decision as to whether or not to conduct such a test is always made by the pregnant woman. 15 Genetic diagnostics in congenital disorders and dysmorphic syndromes Over the past several decades, an increasing proportion of children have been hospitalized at pediatric units or seen at outpatient facilities due to congenital disorders. Thus, these disorders constitute a serious clinical (and diagnostic) problem, as well as a major social and economic issue. Patients with these disorders often present with a complicated history and treatment may not bring the desired medical or social effects. 16 Congenital disorders occur in about 2-3% of live born children, out of which 25-35% is linked to chromosomal aberrations. The incidence of aberrations diagnosed in live born children increases with progress of genetic techniques and higher sensitivity of cytogenetic and molecular tests. 17 Indications for cytogenetic tests in patients with congenital disorders include the following clinical situations: 18 1) presence of phenotypic features characteristic of a specific chromosomal syndrome; 2) presence of multiple developmental defects and/or dysmorphic features; 3) delayed psychomotor development or mental retardation, especially if accompanied by dysmorphic features; 4) abnormal sexual maturation (absent or too early); 5) abnormal appearance of external genitalia; 6) menstruation disturbances of unknown etiology; 7) short stature in girls; 8) suspicion of a chromosomal instability syndrome. If a chromosomal aberration is identified as a cause of a congenital disorder in a child, then thorough advice should be given containing information about the course of the disease and any related congenital defects. This enables extensive early clinical diagnostics (e.g., to detect a heart defect) and preventive care by specialized physicians (e.g., a physiotherapist, speech therapist, 14 Stembalska A, Łaczmańska I, Dudarewicz L. Op. cit.; Stembalska A, Ślęzak R, Pesz K, Gil J, Sąsiadek M M. Op. cit.; Stembalska A, Ślęzak R, Sąsiadek M. Op. cit. 15 Latos-Bieleńska A, Materna-Kiryluk A (ed.). i Zespół ds. PRWWR (Polski rejestr Wad Wrodzonych): Wrodzone wady rozwojowe w Polsce w latach Dane z Polskiego Rejestru Wrodzonych Wad Rozwojowych. OWN. Poznań 2010; Śmigiel R, Ślęzak R, Łaczmańska I, Bateraj-Kubicka B, Bąk E. Zespół Emanuel u noworodka jako skutek rodzinnej, niezrównoważonej translokacji między chromosomami 11 i 22. Pediatria Polska (12). 2005: Latos-Bieleńska A, Materna-Kiryluk A (ed.). Op. cit. 17 Ślęzak R, Strzałkowska A, Czemarmazowicz H, Skulimowska G, Matthews-Brzozowska T. Podwójna trisomia częściowa chromosomów 2 i 14 u dziecka z zespołem cech dysmorficznych. Pediatria Polska (4). 2006: ; Ślęzak R, Łaczmańska I, Busza H, Czemarmazowicz H. Mozaikowa postać częściowej trisomii (de novo) ramion krótkich chromosomu 12 u dziecka z licznymi cechami dysmorficznymi - opis przypadku. Pediatria Polska (8). 2005: ; Ślęzak R, Florjański J, Zalewski J, Sąsiadek M, Heimrath J. Op. cit.; Śmigiel R, Ślęzak R, Łaczmańska I, Bateraj-Kubicka B, Bąk E. Op. cit.; Jacobs P A, Browne C, Gregson N, Joyce C, White H. Estimates of the frequency of chromosome abnormalities detectable in unselected newborns using moderate levels of banding. Medycyna Genetyczna (29). 1992: Śmigiel R, Stembalska A. Niepełnosprawność intelektualna uwarunkowana genetycznie - wybrane aspekty. Nowa Pediatria (R.11). 2007: 89-96; Borg K, Bocian E, Bernaciak J, Nowakowska B, Derwich K, Obersztyn E, Szczałuba K, Śmigiel R, Kostyk E, Mazurczak T. Zrównoważone rearanżacje chromosomowe jako przyczyna niepełnosprawności intelektualnej. Analiza 22 przypadków z wykorzystaniem technik CGH oraz FISH. Medycyna Wieku Rozwojowego (13). 2009: Journal of Health Policy, Insurance and Management Polityka Zdrowotna 41

6 Agnieszka Stembalska, Ryszard Ślęzak, Robert Śmigiel, Maria Małgorzata Sąsiadek psychologist, neurologist, ophthalmologist). If the chromosomal aberration identified in the child is heritable, then other members of the family may be tested, following pedigree analysis. In this way, examination of a child with a congenital disorder may be a point of departure for genetic testing of the entire family, as well as genetic counseling, possibly including indications for prenatal testing. 19 The current algorithm for cytogenetic diagnostics in congenital disorders and mental retardation involves, first of all, exclusion of chromosomal aberrations using classical cytogenetic methods (e.g., G-bands by trypsin using Giemsa, GTG), molecular cytogenetic methods such as fluorescence in situ hybridization (FISH), comparative genomic hybridization (CGH), followed by molecular methods such as multiplex ligation-dependent probe amplification (MLPA). Diagnostics of chromosomal instability syndromes, with symptoms including both congenital defects and mental retardation, is particularly difficult. In cytogenetic diagnostics of such syndromes, it is necessary to use special reagents stimulating chromosomal instability: bleomycin, diepoxybutan, or X-radiation. Cytogenetic examination methods and material Cytogenetic examinations involve evaluation of the structure and number of chromosomes (classical cytogenetics, molecular cytogenetics). The most frequently used classical cytogenetic method, G bands by trypsin using Giemsa (GTG), enables the detection of numerical chromosomal aberrations and structural changes of a size of base pairs (bp). 20 Molecular cytogenetic methods are used for detecting smaller chromosomal aberrations (microaberrations). These include FISH using probes hybridizing with specific regions, which makes it possible to detect changes in the range of kbp. However, this technique requires a precise clinical diagnosis. 21 An alternative technique for examining unbalanced microaberrations is MLPA, which allows for the detection of a deletion and duplication of individual exons and enables evaluation of up to over forty different loci during one reaction. 22 CGH, known as molecular karyotyping, allows for the detection of structural changes of the order of 3 Mbp. Its sensitivity may be greatly enhanced by using microarrays (array-cgh), which enables the detection of microaberrations in the range of 1 Mbp to 15 kbp. 23 FISH, CGH and MLPA may also be used for detecting numerical chromosomal aberrations. In the case of couples presenting with reproductive failure as well as children and adults with congenital disorders and/or intellectual retardation, the material typically used for cytogenetic examinations consists of peripheral blood lymphocytes. In prenatal cytogenetic examinations, specimens include trophoblast cells (trophoblast biopsy in the 10 th -14 th week of pregnancy), amniotic fluid cells (amniocentesis in the 15 th -19 th week of pregnancy), or cord blood lymphocytes (cordocentesis after the 19 th week of pregnancy). 24 In the case of some genetic disorders, it may be useful to acquire other tissues for cytogenetic examination, e.g., skin fibroblasts (in the case 19 Kozłowska J, Łaczmańska I. Badania cytogenetyczne i molekularne wykorzystywane w diagnostyce chorób uwarunkowanych genetycznie. Diagnostyka Laboratoryjna (44). 2008: Palomares M, Delicado A, Lapunzina P, Arjona D, Amiñoso C, Arcas J, Martinez Bermejo A, Fernández L, López Pajares I. MLPA vs multiprobe FISH. comparison of two methods for the screening of subtelomeric rearrangements in 50 patients with idiopathic mental retardation. Clinical Genetics (69). 2006: Łaczmańska I, Łaczmański Ł. Metoda MLPA oraz jej zastosowanie w diagnostyce chorób uwarunkowanych genetycznie. Postępy Biologii Komórki (36). 2009: ; Palomares M, Delicado A, Lapunzina P, Arjona D, Amiñoso C, Arcas J, Martinez Bermejo A, Fernández L, López Pajares I. Op. cit.; Kozłowska J, Łaczmańska I. Op.cit. 22 Śmigiel R, Stembalska A. Op. cit.; Kozłowska J, Łaczmańska I. Op. cit.; Kutkowska-Kaźmierczak A, Obersztyn E, Helias-Rodzewicz Z, Bocian E, Mazurczak T. Subtelomeric aberration as a cause of severe somatic and psychomotor retardation in a child with dysmorphic features and CNS defects. Medycyna Wieku Rozwojowego (8). 2004: ; Coe B P, Ylstra B, Carvalho B, Meijer GA, Macaulay C, Lam W L. Resolving the resolution of array CGH. Genomics (89). 2007: Łaczmańska I, Stembalska A, Ślęzak R, Kozłowska J, Makowska I, Czemarmazowicz H, Pesz K A, Śmigiel R, Jakiel A, Sąsiadek M M. Rapid-FISH jako szybka metoda wykrywania najczęstszych liczbowych aberracji chromosomowych w diagnostyce prenatalnej u kobiet z grupy wysokiego ryzyka. Ginekologia Polska (12). 2007: ; Gil J, Pesz K, Sąsiadek M M, Stembalska A, Ślęzak R. Op. cit.; Stembalska A, Ślęzak R, Pesz K, Gil J, Sąsiadek M M. Op. cit Nr XII/II

7 Cytogenetic examinations in the healthcare system: their potential role in prevention of diseases of a suspected chromosomal mosaic, such as the Pallister Killian syndrome, which is caused by the occurrence of tetrasomy and/or trisomy of chromosome 12p in a mosaic), gonadal tissue in some sex determination disorders, and trophoblast or fetal tissues in the case of aborted fetuses. Summary The identification of chromosomal aberrations is important not only with a view to giving the patient a correct prenatal or postnatal diagnosis and implementing adequate therapeutic and preventive management; it also enables the identification of carriers of chromosomal aberrations in the patient s family, who may then be provided with appropriate health hare. References 1. Anderson C L, Brown C L. Fetal chromosomal abnormalities. antenatal screening and diagnosis (79). American Family Physician Baka-Ostrowska M. Noworodek z obojnaczymi narządami płciowymi. Przegląd Chirurgii Dziecięcej (4) Ball R H. Invasive fetal testing. Current Opinion in Obstetrics and Gynecology (16) Borg K, Bocian E, Bernaciak J, Nowakowska B, Derwich K, Obersztyn E, Szczałuba K, Śmigiel R, Kostyk E, Mazurczak T. Zrównoważone rearanżacje chromosomowe jako przyczyna niepełnosprawności intelektualnej. Analiza 22 przypadków z wykorzystaniem technik CGH oraz FISH. Medycyna Wieku Rozwojowego (13) Branch D W, Gibson M, Silver R M. Reccurent miscarriage. New England Journal of Medicine (363) Coe B P, Ylstra B, Carvalho B, Meijer G A, Macaulay C, Lam W L. Resolving the resolution of array CGH. Genomics (89) Dangel T. Wady letalne u noworodków, opieka paliatywna jako alternatywa wobec aborcji i uporczywej terapii. Standardy Medycyny (9) Dutta U R, Rajitha P, Pidugu V K, Dalal A B. Cytogenetic abnormalities in 1162 couples with recurrent miscarriages in Southern region of India: report and review. Journal of Assisted Reproduction and Genetics (28) Jacobs P A, Browne C, Gregson N, Joyce C, White H. Estimates of the frequency of chromosome abnormalities detectable in unselected newborns using moderate levels of banding. Journal of Medical Genetics (29) Kozłowska J, Łaczmańska I. Badania cytogenetyczne i molekularne wykorzystywane w diagnostyce chorób uwarunkowanych genetycznie. Diagnostyka Laboratoryjna (44) Kutkowska-Kaźmierczak A, Obersztyn E, Helias-Rodzewicz Z, Bocian E, Mazurczak T. Subtelomeric aberration as a cause of severe somatic and psychomotor retardation in a child with dysmorphic features and CNS defects. Medycyna Wieku Rozwojowego (8) Latos-Bieleńska A, Materna-Kiryluk A (ed.) i Zespół ds. PRWWR (Polski Rejestr Wad Wrodzonych). Wrodzone wady rozwojowe w Polsce w latach Dane z Polskiego Rejestru Wrodzonych Wad Rozwojowych. OWN. Poznań Lebedev I. Mosaic aneuploidy in early fetal losses, Cytogenetics and Genome Research (133) Le Caignec C, Spits C, Sermon K, De Rycke M, Thienpont B, Debrock S, Staessen C, Moreau Y, Fryns J P, Van Steirteghem A, Liebaers I, Vermeesch J R. Single-cell chromosomal imbalances detection by array CGH. Nucleic Acids Research (e68). 16. Łaczmańska I, Łaczmański Ł. Metoda MLPA oraz jej zastosowanie w diagnostyce chorób uwarunkowanych genetycznie. Postępy Biologii Komórki (36) Łaczmańska I, Stembalska A, Ślęzak R, Kozłowska J, Makowska I, Czemarmazowicz H, Pesz KA, Śmigiel R, Jakiel A, Sąsiadek M M. Rapid-FISH jako szybka metoda wykrywania najczęstszych liczbowych aberracji chromosomowych w diagnostyce prenatalnej u kobiet z grupy wysokiego ryzyka. Ginekologia Polska (12) Otter M, Schrander-Stumpel C, Curfs L. Triple X syndrome: A review of the literature. European Journal of Human Genetics (18) Palomares M, Delicado A, Lapunzina P, Arjona D, Amiñoso C, Arcas J, Martinez Bermejo A, Fernández L, López Pajares I. MLPA vs multiprobe FISH. comparison of two methods for the screening of subtelomeric rearrangements in 50 patients with idiopathic mental retardation. Clinical Genetics (69) Pasińska M, Haus O, Skonieczka K, Ślęzak R, Midro AT, Stasiewicz-Jarocka B, Szczepaniak M, Adamczak R, Marcinkowska A, Bartusiak K. 9. Gil J, Pesz K, Sąsiadek M M, Stembalska A, Wyniki badań cytogenetycznych i molekularnych u 35 par z niepłodnością pierwotną. Wiadomości Ślęzak R. Genetyczna diagnostyka prenatalna, Lekarskie (1-2) metody badań, elementy poradnictwa genetycznego. Badania Diagnostyczne (7-8) Journal of Health Policy, Insurance and Management Polityka Zdrowotna 43

8 Agnieszka Stembalska, Ryszard Ślęzak, Robert Śmigiel, Maria Małgorzata Sąsiadek 21. Pergament E. First-Trimester Genetic Counseling: Perspectives and Considerations. Clin Lab Med (30) Program Badań Prenatalnych, Załącznik nr 5 do zarządzenia Nr 53/2006 Prezesa Narodowego Funduszu Zdrowia. 23. Rekomendacje Polskiego Towarzystwa Ginekologicznego dotyczące postępowania w zakresie diagnostyki prenatalnej. Opracowanie zespołu ekspertów. Ginekologia Polska (80) Sąsiadek M M, Haus O, Łukasik-Majchrowska M, Ślęzak R, Paprocka-Borowicz M, Busza H, Plewa R, Bułło A, Jagielski J. Badania cytogenetyczne u małżeństw z poronieniami samoistnymi. Ginekologia Polska (5a) Schoolcraft W B, Katz-Jaffe M G, Stevens J, Rawlins M, Munne S. Preimplantation aneuploidy testing for infertile patients of advanced maternal age: a randomized prospective trial. Fertility and Sterility (92) Sharma G, McCullough L B, Chervenak FA. Ethical considerations of early (first vs. second trimester) risk assessment disclosure for trisomy 21 and patient choice in screening versus diagnostic testing. American Journal of Medical Genetics Part C Seminars in Medical Genetics (145C) Stembalska A, Łaczmańska I, Dudarewicz L. Nieinwazyjne badania prenatalne w diagnostyce aneuploidii chromosomów 13, 18 i 21 - aspekty teoretyczne i praktyczne. Ginekologia Polska (2) Stembalska A, Ślęzak R, Pesz K, Gil J, Sąsiadek M M. Prenatal diagnosis - principles of diagnostic procedures and genetic counseling. Folia Histochemica et Cytobiologica (45) Supplement : Stembalska A, Ślęzak R, Sąsiadek M. Badania prenatalne. Family Medicine and Primary Care Review (1) Ślęzak R, Strzałkowska A, Czemarmazowicz H, Skulimowska G, Matthews-Brzozowska T. Podwójna trisomia częściowa chromosomów 2 i 14 u dziecka z zespołem cech dysmorficznych. Pediatria Polska (4) Ślęzak R, Łaczmańska I, Busza H, Czemarmazowicz H. Mozaikowa postać częściowej trisomii (de novo) ramion krótkich chromosomu 12 u dziecka licznymi cechami dysmorficznymi - opis przypadku. Pediatria Polska (8) Ślęzak R, Florjański J, Zalewski J, Sąsiadek M, Heimrath J. Diagnostyka prenatalna triploidii. Ginekologia Polska (4) Ślęzak R. Propozycje postępowania diagnostycznego w zespole Turnera. Biuletyn Informacyjny Komisji Genetyki Człowieka (7) Ślęzak R, Sąsiadek M, Dobosz T, Gogulska L, Jagielski J. Oznaczanie swoistych sekwencji chromosomu Y w zespole Turnera. Ginekologia Polska (9) Śmigiel R, Stembalska A. Niepełnosprawność intelektualna uwarunkowana genetycznie - wybrane aspekty. Nowa Pediatria (R.11) Śmigiel R, Ślęzak R, Łaczmańska I, Bateraj- Kubicka B, Bąk E. Zespół Emanuel u noworodka jako skutek rodzinnej, niezrównoważonej translokacji między chromosomami 11 i 22. Pediatria Polska (12) Ustawa o planowaniu rodziny, ochronie płodu ludzkiego i warunkach dopuszczalności przerywania ciąży z dnia 7 stycznia 1993 r. (z 1993 r., Dz.U. Nr 17, poz. 78; z 1995 r., Nr 66, poz. 334, z 1996 r., Nr 139, poz. 646, z 1997 r. Nr 141, poz. 943, Nr 157, poz i z 1999 r. Nr 5, poz. 32). 38. Zhang L, Zhang X-H, Linag M Y, Ren M H. Prenatal cytogenetic study of 2782 cases of highrisk pregnant women. Chinese Medical Journal (123) Nr XII/II