Chromosome abnormalities identified in 457 spontaneous abortions and their histopathological findings

OBJECTIVE

About 15% of clinically recognized pregnancies result in spontaneous abortion in the first trimester and the vast majority of these are the result of chromosome abnormalities. Studies of chromosomal constitutions of first trimester spontaneous abortions have revealed that at least 50% of the abortions have an abnormal karyotype. In this study we aimed to report the single centre experience of anomalies detected in spontaneous abortions.

MATERIAL AND METHOD

We present rare numerical and structural cytogenetic abnormalities detected in spontaneous abortion materials and the histopathological findings of rest material of abortion specimens in our study population.

RESULTS

Among 457 cases, 382 were successfully karyotyped while cell culture of 75 cases failed. Cytogenetic abnormalities were detected in 127 of 382 cases (33.24%). Autosomal trisomies were the predominant chromosomal abnormalities with a frequency of 48.8%. Structural chromosomal abnormalities were infrequent in conception materials. The mean age of the mothers was highest in trisomy group, the difference being significantly important (ANOVA p < 0.001). The most frequent chromosomal abnormalities were Turner syndrome, triploidy and trisomy of chromosome 16 followed by trisomy of chromosomes 22 and 21 and tetraploidy. Double trisomies and structural chromosomal abnormalities were rare. Trisomies were more frequent in advanced maternal age.

CONCLUSION

Detection of chromosomal abnormalities in spontaneous abortion materials is very important to clarify the causes of loss of pregnancy. Detection of structural chromosomal abnormalities in the cases and their carrier parents can provide proper genetic counseling to these families. These families can be directed towards pre-implantation genetic diagnosis to prevent further pregnancies with complications.

Mitochondrial ATPase subunit 6 and cytochrome B gene variations in obese Turkish children

OBJECTIVE

Due to the importance of energy metabolism in mitochondria, mitochondrial genome variations are evaluated in energy-related diseases such as obesity. To date, several nuclear genes were found to be related to obesity. Our aim in this study was to investigate the presence of polymorphisms in mitochondrial ATPase subunit 6 (mt-ATP6) and cytochrome b (mt-CytB) genes that may be associated with childhood obesity.

METHODS

The mt-ATP6 and mt-CytB genes were amplified and entirely sequenced in a series of 100 obese and in an equal number of healthy Turkish children aged between 6-14 years.

RESULTS

A total of 118 synonymous and nonsynonymous variations were detected in the obese and control groups. Only two previously reported synonymous substitutions (mt.8614T>C and mt.8994G>A) in the mt-ATP6 gene were found to be significantly higher in the obese group compared to the control group (p<0.05). In the mt-ATP6 gene, one novel nonsynonymous substitution (mt.8726C>T) and one novel synonymous substitution (mt.9108A>T) were found. In the mt-CytB gene, one nonsynonymous substitution (mt.14880T>C) and two synonymous substitutions (mt.14891C>T and mt.15091C>T) were novel substitutions.

CONCLUSION

Two synonymous substitutions (mt.8614T>C and mt.8994G>A) in the mt-ATP6 gene may be associated with childhood obesity. Our study provides the first data about mitochondrial genome variations in a Turkish obese population and also the first in obese children. More cases should be screened in obese groups in order to understand the effects of mitochondrial polymorphisms in the development of obesity.

Rare structural chromosomal abnormalities in prenatal diagnosis; clinical and cytogenetic findings on 10125 prenatal cases

Objective: The aim of this study was presentation of the ultrasonographic findings and perinatal autopsy of cases with rare chromosomal abnormalities.

MATERIAL AND METHOD

A total of 10125 prenatal cases over 17 years including 8731 amniocentesis, 973 chorionic villus sampling, and 421 fetal blood sampling cases were evaluated for prenatal cytogenetic diagnosis. Conventional cytogenetic studies, fluorescence in situ hybridization studies, and Array-CGH analysis techniques were used for genetic analysis.

RESULTS

A structural chromosomal abnormality was observed in 95 cases. The most frequently observed structural abnormalities were balanced translocations with a frequency of 53.7% (51 cases) followed by unbalanced translocations (16.8%), inversions (11.6%), supernumerary marker chromosomes (8.4%), duplications (4.2%), deletions and ring chromosomes (2.1%) and complex translocation (1.1%). Rare structural chromosomal abnormalities including de novo balanced translocations, unbalanced translocations, inversions, duplications, deletions, ring chromosomes, and supernumerary marker chromosomes were detected in 24 cases.

CONCLUSION

The rate of rare chromosomal abnormalities varies from 2.4% (South East Ireland) to 12.9% (Northern England) in Europe with a total rate of 7.4/10 000 births. In our study, the overall rate of chromosomal abnormality in prenatal cytogenetic diagnosis was 3.7%, similar to South East Ireland. Ultrasonographic and perinatal autopsy findings of the cases with rare structural chromosomal abnormalities are important for proper genetic counseling for further similar cases.

Clinicogenetic study of Turkish patients with syndromic craniosynostosis and literature review

BACKGROUND

Fibroblast growth factor receptor 2 mutations have been associated with the craniosynostotic conditions of Apert, Crouzon, Pfeiffer, Saethre-Chotzen, Jackson-Weiss, Beare-Stevenson cutis gyrata, and Antley-Bixler syndromes in various ethnic groups.

METHODS

Thirty-three unrelated Turkish patients (12 with Apert syndrome, 14 with Crouzon syndrome, six with Pfeiffer syndrome, and one with Saethre-Chotzen syndrome) and 67 nonsyndromic craniosynostosis patients were screened for mutations in exons IIIa and IIIc of the FGFR2 gene by denaturing high-performance liquid chromatography and confirmed by direct sequencing.

RESULTS

We detected several pathogenic mutations in 11/33 (33%) patients with Apert syndrome (four with p.Pro253Arg; seven with p.Ser252Trp) and 8/33 (24%) patients with Crouzon syndrome (three with p.Trp290Arg, one with p.Cys342Tyr, p.Cys278Phe, p.Gln289Pro, and a novel p.Tyr340Asn mutation) and five (15%) with Pfeiffer syndrome (p.Cys342Arg, p.Pro253Arg, p.Trp290Arg, and p.Ser351Cys). No FGFR2 gene mutation was detected in any of the patients with Saethre-Chotzen syndrome and nonsyndromic craniosynostosis.

CONCLUSIONS

Our results indicate that the majority of Turkish patients with syndromic craniosynostosis have detectable genetic changes with an overall frequency of 72.7%. Because this is the first molecular genetic report from a Turkish cohort, the identified spectrum profile of FGFR2 mutations of the syndromic craniosynostotic patients would be very helpful for understanding the genotype-phenotype relationship and has a great value for diagnosis, prognosis, and genetic counseling.

The association of Klinefelter syndrome and multiple pterygium syndrome: an unusual presentation

Multiple pterygium syndrome is characterized by a number of phenotypic features, small stature, webbing of the neck, elbows, and/or knees, and joint contractures. In this report, we present an 11-year-old boy who had the classical findings of multiple pterygium syndrome, and his chromosomal analysis revealed a 47,XXY karyotype. Interestingly, he did not show any of the main clinical signs of Klinefelter syndrome. This patient appears to be the first reported case in the literature in which a non-mosaic 47,XXY karyotype has been found in a patient with multiple pterygium syndrome. The aim of the present report is to describe a non-classic Klinefelter syndrome associated with multiple pterygium syndrome and to emphasize the importance of karyotype analysis in patients with multiple pterygium syndrome.

Aplasia cutis congenita: three cases with three different underlying etiologies

Aplasia cutis congenita (ACC) is an uncommon condition in which localized or widespread areas of skin are absent or scarred at birth. There is no single underlying cause of ACC, as it simply represents a physical finding that reflects a disruption of intrauterine skin development. Here we report three cases of ACC of the scalp with three different etiologies: congenital rubella syndrome, trisomy 13 and fetal valproate syndrome. The aim of the present report is to increase awareness of these skin defects and emphasize the importance of underlying etiologies.

Subtelomeric rearrangements of dysmorphic children with idiopathic mental retardation reveal 8 different chromosomal anomalies

Subtelomeric rearrangements are an important cause of both sporadic and familial idiopathic mental retardation (MR) and/or congenital malformation syndromes. We report on a cohort of 107 children with idiopathic MR and normal karyotype 450-550 band level by GTG banding screened for subtelomeric rearrangements by multiprobe fluorescence in situ hybridization (FISH). In these cases, five patients had de novo deletions (1p deletion was found in 2 cases; 3q deletion, 9p and 9q deletions were found in 1 case each) and four patients had unbalanced rearrangements [der(5)t(5;15)(pter;qter)pat in 2 patients who were siblings, rec(10)dup(10p)inv(10)(p13q26)mat in 1 patient and der(18)t(18;22)(qter;qter) de novo in 1 patient]. Our study confirms that the subtelomeric rearrangements are a significant cause of idiopathic MR with dysmorphic features.

Prenatal diagnosis of a de novo supernumerary marker chromosome originating from chromosome 16

Prenatal diagnosis of a de novo supernumerary marker chromosome originating from chromosome 16: A 37 year old pregnant woman was referred for amniocentesis at 18 weeks of gestation due to advanced maternal age and abnormal serum biochemistry. A nonsatellited, monocentric marker chromosome was observed with a frequency of 57% in cultured amniocytes. Parental karyotypes were normal. The marker chromosome was found to be derived from chromosome 16 by FISH using CEP16 and WCP16 probes. Marker chromosomes were not painted with M-FISH probe mixture, indicating an exclusively heterochromatin nature. CGH analysis using genomic DNA isolated from uncultured amniocytes also supported the M-FISH results. Genetic counseling was given to parents and the family decided to continue the pregnancy to term. The baby was born at 36 weeks of gestation without any dysmorphic features. Follow-up at 7 months of age revealed no developmental abnormalities.

A rare case of Turner's syndrome with 45,X/46,X,Dic (X) (qter----p11.1::p11.4----qter)

This paper presents a female patient with clinical features of Turner's Syndrome and the chromosomal constitution of 45,X/46,X,dic (X) (qter----p11.1::p11.4----qter). This abnormal X chromosome was compared with similar-structured dic(X).

A hereditary bisatellite-dicentric supernumerary chromosome in a case of cat-eye syndrome

We studied the clinical and cytogenetic features of a case of Cat-eye Syndrome. The chromosomal analysis showed 47 chromosomes. The supernumerary small, metacentric, bisatellited marker chromosome was probably derived from a No. 22 and occurred as well in the proband's sister and mother.

The frequency and medical effects of consanguineous marriages in Antalya, Turkey

We investigated 2604 marriages in Antalya, a region in the Mediterranean coast of Turkey. The 1020 urban and 1584 rural families included in the study were randomly selected and interviewed at their homes by one of the authors. The total consanguinity was 35.2%, rates being 39.6 and 28.3% for rural and urban areas, respectively. The frequency of consanguinity in different age groups did not vary whereas level of education of the women appeared to have a negative correlation. Family pressure and love were stated as the main reasons for marrying with a relative. Differences were observed between consanguineous and non-consanguineous marriages in sterility, infant death, spontaneous abortion, child death and congenital malformations, these being significantly higher in consanguineous matings. Data from similar Turkish studies are also presented and discussed.

Mutational spectrum of MYO15A: the large N-terminal extension of myosin XVA is required for hearing

Human MYO15A is located on chromosome 17p11.2, has 66 exons and encodes unconventional myosin XVA. Recessive mutations of MYO15A are associated with profound, nonsyndromic hearing loss DFNB3 in humans, and deafness and circling behavior in shaker 2 mice. In the inner ear, this motor protein is necessary for the development of hair cell stereocilia, which are actin-filled projections on the apical surface and the site of mechanotransduction of sound. The longest isoform of myosin XVA has 3,530 amino acid residues. Two isoform classes of MYO15A are distinguished by the presence or absence of 1,203 residues preceding the motor domain encoded by alternatively-spliced exon 2. It is not known whether this large N-terminal extension of myosin XVA is functionally necessary for hearing. We ascertained approximately 600 consanguineous families segregating hereditary hearing loss as a recessive trait and found evidence of linkage of markers at the DFNB3 locus to hearing loss in 38 of these families ascertained in Pakistan (n=30), India (n=6), and Turkey (n=2). In this study, we describe 16 novel recessive mutations of MYO15A associated with severe to profound hearing loss segregating in 20 of these DFNB3-linked families. Importantly, two homozygous mutant alleles-c.3313G>T (p.E1105X) and c.3334delG (p.G1112fsX1124) of MYO15A-located in exon 2 are associated with severe to profound hearing loss segregating in two families. These data demonstrate that isoform 1, containing the large N-terminal extension, is also necessary for normal hearing.

Maternal origin and clinical findings in a case with trisomy 22

We report a newborn girl with multiple congenital anomalies whose chromosomal analysis showed complete trisomy 22. Her phenotype included microcephaly, epicanthus, hypertelorism, micrognathia, cleft palate, microtia, and preauricular tag. She died in the 24th post-natal hour. Trisomy 22 was shown by fluorescence in situ hybridization technique and the parental origin of the extra chromosome was found to be maternal by DNA microsatellite marker analysis of chromosome 22. Postmortem examination revealed the presence of atrioseptal defect and stasis in the biliary canals. We believe that this patient will contribute to the literature both by clinical findings and short life span associated with maternal origin of extra chromosome 22.

Psychological effects of amniocentesis on women and their spouses: importance of the testing period and genetic counseling

OBJECTIVE

To evaluate both women's and their spouses' reasons for undergoing amniocentesis, their concerns relating to the procedure as well as their psychological reactions and coping mechanisms during the testing period.

METHODS

Eighty-five women undergoing amniocentesis and their spouses took part in the study. The couples completed a questionnaire that provided demographic data and insights into their experiences of amniocentesis.

RESULTS

Age was the main reason for undergoing amniocentesis. When they first learned that they were going to undergo amniocentesis, women were more concerned about the potential danger to their fetus than their spouses. Most of participants believed that their pregnancy would continue after amniocentesis. However, they also stated that they were prepared for an abortion. Uncertainty and tension were two significant emotions experienced by couples while waiting for the test results. For the majority of women (80%) and men (42.3%) the strongest support was provided by their spouses during this period. In summary, we can conclude that the test did have a major psychological impact on both women and their spouses, but did not have a negative impact on their coping mechanisms.

CONCLUSION

The psychological impact of amniocentesis on women and their spouses does not constitute a major obstacle to their ability to cope. However, a certain number of couples reported feelings of uncertainty, tension and anxiety about fetal injury. We strongly suggest that counseling should be given to high-risk families and that prenatal/antenatal care units must be established.

Consanguineous marriages in the province of Antalya, Turkey

To assess the trends in the frequency and the medical effects of consanguinity in the south coast of Turkish population using local and national data in the last 11 years. This cross-sectional study was carried out in Manavgat province, which is a major tourism center on the Mediterranean coast of Turkey. The authors studied consanguineous marriages in rural and urban population in the Mediterranean coast, Manavgat province, Turkey, via a 1500 random survey sample of married couples. There has been a significant increase in the incidence of consanguineous marriages in rural areas (40.7%) since 1989 in the southern population of Turkey. The results showed that the most frequent type of marriage was between the first cousins. It is found that there is no statistically significant difference between the consanguineous and non-consanguineous marriages in the different age groups. The results were discussed on the basis of educational status, reasons for having consanguineous marriages and the general medical effects as well as with the relation of congenital malformations. The custom of consanguineous unions in the Mediterranean population of Turkey is still extremely high, and preventive measures should be done to decrease its frequency and associated complications.

combination of IVS2.849 A-G witH IVS1.1 G-A: a mutation of beta-globin gene in a Turkish beta-thalessemia major patient

Beta-thalassemia, which is an autosomal recessive disease, is among the most common hemoglobinopathies in Antalya, Turkey. Mutations found in Turkish beta-thalassemia patients constitute a heterogeneous group, which is mostly composed of point mutations and, only in very rare cases, a deletion or an insertion causes affected or carrier phenotypes. Reverse dot blot hybridization (RDBH) method is used for screening common mutations, and sequence analysis and silver staining were performed consecutively to detect any uncommon mutation. The authors report a first Turkish family with a rare variant--intervening sequence 2 (IVS2) 849 (A-G). The proband's mother and father were determined as carriers of IVS2.849 (A-G) and IVS1.1 (G-A) mutations, respectively. Proband is the first child of the family and she has an IVS2.849 (A-G)/IVS1.1 (G-A) genotype with ss-thalassemia major phenotype. Prenatal diagnosis was performed for the second child, and genotype of the fetus was determined as IVS2.849 (A-G)/Normal. This first report of IVS2.849 (A-G) mutation in Turkish population shows that there are many more mutations contributing the heterogeneity of the mutation spectrum of beta-globin gene in the Turkish population, which indicates migrations of different ethnic origins.

Compound heterozygosity for two beta chain variants: the mildly unstable Hb Tyne (codon 5 Pro→Ser) and HbS (codon 6 Glu→Val)

Compound heterozygosity for Hb Tyne and HbS, that is very rare, was identified by direct DNA sequencing of the beta-globin gene in a Turkish patient. Hematological investigation of a girl at the age of 9 due to the presence of HbS (40.7%) led to the identification of a compound heterozygosity at codons 5-6. This was found to be the result of substitution of cytosine (C) for thymidine (T) at the fifth position and a substitution of adenine (A) for thymidine (T) at the sixth position of the beta globin gene. As a result of these mutations, the order of amino acids at codons 5-6 was changed from Pro-Glu to Ser-Val, respectively. Since the co-inheritance of Hb Tyne and HbS had not been reported in literature before, our case set an example for identification of coinheritance of Hb Tyne and HbS for the first time. Therefore, such cases may be considered as an important example for understanding the structural variants of hemoglobin and may provide important clues for critical amino acids responsible for stabilization of hemoglobin tetrameric structure and genetic counseling.

M-FISH applications in clinical genetics

Until recently, presence of de novo marker or derivative chromosomes was quite problematic for genetic counseling especially in prenatal diagnosis, because characterization of marker and derivative chromosomes by conventional cytogenetic techniques was nearly impossible. However, recently developed molecular cytogenetic technique named Multicolor Fluorescence in Situ Hybridization (M-FISH) which paints all human chromosomes in 24 different colors allows us to characterize marker and derivative chromosomes in a single hybridization. In this study, we applied M-FISH to determine the origin of 3 marker and 3 derivative chromosomes. Marker chromosomes were found to originate from chromosome 15 in two postnatal and one prenatal case. Of these, one of the postnatal cases displayed clinical findings of inv dup (115) syndrome and the other of infertility, and the prenatal case went through amniocentesis due to the triple test results. Karyotypes of the patients with derivative chromosomes were designated as 46,XY,der (21)t(1;21)(q32;p11), 46,XX,der(8)t(8;9)(p23;p22) and 46,XX,der(18)t(18;20)(q32;p11.2) according to cytogenetic and M-FISH studies. All of the M-FISH results were confirmed with locus specific or whole chromosome painting probes. The case with der (8)t(8;9) had trisomy 9(p22-pter) and monosomy 8(p23-pter) due to this derivative chromosome. The case with der(18)t(18;20) had trisomy 20(p11.2-pter) and monosomy 18(q32-qter). Parental origins of the derivative chromosomes were analyzed using microsatellite markers located in the trisomic chromosomal segments. Patients' clinical findings were compared with the literature.

A case with de novo interstitial deletion of chromosome 7q21.1-q22

A case with de novo interstitial deletion of chromosome 7q21.1-q22: A patient with multiple congenital anomalies was found to have a de novo proximal interstitial deletion of chromosome 7q21.1-q22. The patient was 10.5 years of age, and manifestations include growth retardation (below 3rd percentile), mental retardation, mild microcephaly, hypersensitivity to noise, mild spasticity, short palpebral fissures, alternant exotropia, compensated hypermetropic astigmatism, hypotelorism, hypoplastic labia majora and minora, clinodactyly of fingers 4 and 5. Molecular studies revealed that the deletion had a paternal origin, while chromosomes of both parents cytogenetically were shown to be normal. Molecular, and fluorescence in situ hybridization (FISH) analyses confirmed no deletion at the Williams-Beuren Syndrome region. Some of the heterogeneous clinical findings were consistent with previously reported cases of same chromosomal breakpoints.

Lack of association between RNASEL Arg462Gln variant and the risk of breast cancer

BACKGROUND

The RNASEL G1385A variant was recently found to be implicated in the development of prostate cancer. Considering the function of RNase L and the pleiotropic effects of mutations associated with cancer, we sought to investigate whether the RNASEL G1385A variant is a risk factor for breast cancer.

PATIENTS AND METHODS

A total of 453 breast cancer patients and 382 age- and sex-matched controls from Greece and Turkey were analyzed. Genotyping for the RNASEL G1385A variant was performed using an Amplification Refractory Mutation System (ARMS).

RESULTS

Statistical evaluation of the RNASEL G1385A genotype distribution among breast cancer patients and controls revealed no significant association between the presence of the risk genotype and the occurrence of breast cancer.

CONCLUSION

Although an increasing number of studies report an association between the RNASEL G1385A variant and prostate cancer risk; this variant does not appear to be implicated in the development of breast cancer.

AZF microdeletions on the Y chromosome of infertile men from Turkey

Intervals V and VI of Yq11.23 regions contain responsible genes for spermatogenesis, and are named as "azoospermia factor locus" (AZF). Deletions in these genes are thought to be pathogenetically involved in some cases of male infertility associated with azoospermia or oligozoospermia. The aim of this study was to establish the prevalence of microdeletions on the Y chromosome in infertile Turkish males with azoospermia or oligozoospermia. We applied multiplex polymerase chain reaction (PCR) using several sequence-tagged site (STS) primer sets, in order to determine Y chromosome microdeletions. In this study, 61 infertile males were enrolled for the molecular AZF screening program. In this cohort, one infertile male had 46,XX karyotype and the remaining had 46,XY karyotypes. Forty-eight patients had a diagnosis of azoospermia and 13 had oligozoospermia. Microdeletions in AZFa, AZFb and AZFc (DAZ gene) regions were detected in two of the 60 (3.3%) idiopathic infertile males with normal karyotypes and a SRY translocation was determined on 46,XX male. Our findings suggest that genetic screening should be advised to infertile men before starting assisted reproductive treatments.

Germline mutations in the BRCA1 and BRCA2 genes in Turkish breast/ovarian cancer patients

In this study we genotyped Turkish breast/ovarian cancer patients for BRCA1/BRCA2 mutations: protein truncation test (PTT) for exon 11 BRCA1 of and, multiplex PCR and denaturing gradient gel electrophoresis (DGGE) for BRCA2, complemented by DNA sequencing. In addition, a modified restriction assay was used for analysis of the predominant Jewish mutations: 185delAG, 5382InsC, Tyr978X (BRCA1) and 6174delT (BRCA2). Eighty three breast/ovarian cancer patients were screened: twenty three had a positive family history of breast/ovarian cancer, ten were males with breast cancer at any age, in eighteen the disease was diagnosed under 40 years of age, one patient had ovarian cancer in addition to breast cancer and one patient had ovarian cancer. All the rest (n=30) were considered sporadic breast cancer cases. Overall, 3 pathogenic mutations (3/53-5.7%) were detected, all in high risk individuals (3/23-13%): a novel (2990insA) and a previously described mutation (R1203X) in BRCA1, and a novel mutation (9255delT) in BRCA2. In addition, three missense mutations [two novel (T42S, N2742S) and a previously published one (S384F)] and two neutral polymorphisms (P9P, P2532P) were detected in BRCA2. Notably none of the male breast cancer patients harbored any mutation, and none of the tested individuals carried any of the Jewish mutations. Our findings suggest that there are no predominant mutations within exon 11 of the BRCA1 and in BRCA2 gene in Turkish high risk families.

Evaluation of complex inheritance involving the most common Bardet-Biedl syndrome locus (BBS1)

Bardet-Biedl syndrome (BBS) is a genetic disorder with the primary features of obesity, pigmentary retinopathy, polydactyly, renal malformations, mental retardation, and hypogenitalism. Patients with BBS are also at increased risk for diabetes mellitus, hypertension, and congenital heart disease. BBS is known to map to at least six loci: 11q13 (BBS1), 16q21 (BBS2), 3p13-p12 (BBS3), 15q22.3-q23 (BBS4), 2q31 (BBS5), and 20p12 (BBS6). Although these loci were all mapped on the basis of an autosomal recessive mode of inheritance, it has recently been suggested-on the basis of mutation analysis of the identified BBS2, BBS4, and BBS6 genes-that BBS displays a complex mode of inheritance in which, in some families, three mutations at two loci are necessary to manifest the disease phenotype. We recently identified BBS1, the gene most commonly involved in Bardet-Biedl syndrome. The identification of this gene allows for further evaluation of complex inheritance. In the present study we evaluate the involvement of the BBS1 gene in a cohort of 129 probands with BBS and report 10 novel BBS1 mutations. We demonstrate that a common BBS1 missense mutation accounts for approximately 80% of all BBS1 mutations and is found on a similar genetic background across populations. We show that the BBS1 gene is highly conserved between mice and humans. Finally, we demonstrate that BBS1 is inherited in an autosomal recessive manner and is rarely, if ever, involved in complex inheritance.

Existence of acute lymphoblastic leukemia and osteosarcoma in a child

The existence of acute lymphoblastic leukemia (ALL) and osteosarcoma is described. An 8-year-old girl had osteosarcoma diagnosed on radiologic and pathologic examination during ALL maintenance treatment. Cytogenetic analyses in primary cell culture of osteosarcoma tissue from the patient showed complex chromosomal abnormalities including t(1;19), usually seen in B precursor cell ALL, and del 13, found in a great majority of primary osteosarcomas. To show the possibility of the existence of the genetic susceptibility caused by gene rearrangements, we used molecular technique. But we could not determine any association between gene and genetic susceptibility.

Identification of the gene (BBS1) most commonly involved in Bardet-Biedl syndrome, a complex human obesity syndrome

Bardet-Biedl syndrome (BBS, OMIM 209900) is a genetic disorder with the primary features of obesity, pigmentary retinopathy, polydactyly, renal malformations, mental retardation and hypogenitalism. Individuals with BBS are also at increased risk for diabetes mellitus, hypertension and congenital heart disease. What was once thought to be a homogeneous autosomal recessive disorder is now known to map to at least six loci: 11q13 (BBS1), 16q21 (BBS2), 3p13 p12 (BBS3), 15q22.3 q23 (BBS4), 2q31 (BBS5) and 20p12 (BBS6). There has been considerable interest in identifying the genes that underlie BBS, because some components of the phenotype are common. Cases of BBS mapping ro BBS6 are caused by mutations in MKKS; mutations in this gene also cause McKusick-Kaufman syndrome (hydrometrocolpos, post-axial polydactyly and congenital heart defects). In addition, we recently used positional cloning to identify the genes underlying BBS2 (ref. 16) and BBS4 (ref. 17). The BBS6 protein has similarity to a Thermoplasma acidophilum chaperonin, whereas BBS2 and BBS4 have no significant similarity to chaperonins. It has recently been suggested that three mutated alleles (two at one locus, and a third at a second locus) may be required for manifestation of BBS (triallelic inheritance). Here we report the identification of the gene BBS1 and show that a missense mutation of this gene is a frequent cause of BBS. In addition, we provide data showing that this common mutation is not involved in triallelic inheritance.

Netherton syndrome associated with idiopathic congenital hemihypertrophy

Netherton syndrome is a rare genodermatosis comprised of anichthyosiform dermatitis, hair shaft defects, and atopic features. Other problems associated with Netherton syndrome are delayed growth and development, immune abnormalities, recurrent infections, and intermittent aminoaciduria. We describe an 18-month-old girl with Netherton syndrome who had idiopathic congenital hemihypertrophy on her right side with contralateral benign nephromegaly in addition to the characteristic clinical signs of the syndrome. To our knowledge, this is the first case of Netherton syndrome associated with idiopathic congenital hemihypertrophy to be reported.

Detection of LOH of the RB1 gene in bladder cancers by PCR-RFLP

OBJECTIVES

Retinoblastoma (RB1) gene involves in retinoblastoma, osteosarcoma, bladder, prostate, lung, breast carcinomas, and soft tissue sarcomas. Loss of heterozygosity (LOH) is the most common mutation of the gene.

METHODS

Xba I polymorphism in intron 17 of the gene was used to detect LOH in 20 bladder cancer patients. A cystitis and an osteosarcoma were used as control. LOH was investigated in three different kinds of samples (blood, paraffin-embedded tissue and fresh tissue) belonging to the same patients, and 20 blood samples, 20 paraffin-embedded tissue samples and 16 fresh tissue samples were obtained from 20 cancer patients.

RESULTS

None of the 20 blood samples showed LOH. Eleven out of 20 paraffin-embedded bladder tissues were amplified, 3 of them homozygous and all 8 informative paraffin-embedded tissues showed LOH. Five out of 16 fresh tumor tissues obtained were amplified, in 1 the fresh tissue was normal, 1 fresh tissue showed LOH and 3 were not digested by Xba I.

CONCLUSION

The results of the study have suggested that detection of LOH of the RB1 gene by PCR-RFLP can be a good adjunctive test for evaluation of the bladder cancer.

Telomere-specific fluorescence in situ hybridization analysis of couples with five or more recurrent miscarriages

Fluorescence in situ hybridization analysis using telomere specific probes has been used to detect cryptic translocations in the chromosomal telomeric regions. This study was performed in five clinically normal couples who have had five or more spontaneous abortions and whose karyotypes were found to be normal using conventional cytogenetic techniques. Using the telomere specific probes, in one couple we determined a cryptic translocation between chromosome 3 and 10, and, in another couple, the signal in chromosome 20 was detected in another chromosome, which was probably a D group chromosome. Additionally, in the latter and also in two other couples, we observed a polymorphism. The approach will be helpful for screening cryptic translocations using telomere specific multiple probe sets in couples with recurrent miscarriages. As prenatal diagnosis will be available for these couples for future pregnancies, it will be possible to help these families to have healthy fetuses.

Comparative genomic hybridization in ganglioneuroblastomas

The ganglioneuroblastoma are rare lesions with widespread neuronal differentiation that have been classified as intermediate stages between neuroblastoma and ganglioneuroma. To identify overall chromosome aberrations in ganglioneuroblastoma, we performed comparative genomic hybridization. All of the five tumor samples were found to exhibit multiple gains involving different chromosomal regions. Chromosomal gains displayed by chromosomes and chromosome loci were 2p25 approximately pter (60%), 5p15.1 approximately p15.3 (60%), 7 (60%), 13q22 approximately q31 (60%), and 22 (60%), which were detected as minimal common regions in all five tumor samples. Chromosome 22 gain, which had not been reported in neuronal tumors before, and novel site 13q22 approximately q31 may be considered to play an important role in progression and differentiation of ganglioneuroblastoma.

Maternal serum screening for Down's syndrome, open neural tube defects and trisomy 18

Maternal serum screening identifies women at an increased risk of a pregnancy with Down's syndrome or trisomy 18 or an open neural tube defect. The triple test, consisting of maternal serum alpha-fetoprotein, unconjugated estriol and human chorionic gonadotropin was carried out by a chemiluminescence immunoassay method in our laboratory. The study consisted of 373 pregnant women. The gestational range for the study group was 14-22 weeks. The mean maternal age for the study group was 28.53 +/- 5.46 years (range 17.4 to 43.5 years); 9.1% of the women were considered at high risk for Down's syndrome based on the test results. In our study the detection rate for Down's syndrome by prenatal karyotyping was 66.6%. Maternal serum screening allows reduction of the number of women requiring amniocentesis without a significant decrease in the detection rate.

The effect of hydroxyurea on rabbit subconjunctival fibroblast culture and use of hydroxyurea in rabbits after glaucoma filtration surgery

In an in vitro study, rabbit subconjunctival fibroblasts were cultured and the effects of an antineoplastic drug, hydroxyurea (HU), on fibroblast proliferation and fibroblast attachment was investigated. The effects of HU were compared with those of mitomycin C (MMC). Different concentrations of HU and MMC were added to culture medium. The HU doses which led to 50% of inhibition (ID(50)) and the dose which led to about 90% of inhibition (subtoxic high dose, STHD) were determined to be 8 and 1,000 microg/ml, respectively. ID(50) of MMC and its STHD which led to about 100% inhibition were found to be 0.01 and 1 microg/ml, respectively. Reversibility studies revealed that inhibition disappeared depending on the dose and incubation period of both HU and MMC. In an in vivo study, glaucoma filtration surgery (GFS) was performed in rabbits which were treated with HU (treatment group) and distilled water (control group). Tissue samples were taken from the subconjunctival area treated at 1 h, 1 day, 5 days and 30 days postoperatively. The biopsy specimens were then placed in tissue culture media. Fibroblast outgrowth rates detected in the HU group were found to be significantly lower than those in the control group in the specimens taken at the end of the first hour. The difference was significant on culture days 9-15 in the biopsy specimens taken on day 1 while it was not significant in those taken on days 5 and 30.

Nucleotide changes in the gamma-globin promoter and the (AT)xNy(AT)z polymorphic sequence of beta LCRHS-2 region associated with altered levels of HbF

We have studied 31 beta-thalassaemia intermedia, 30 beta-thalassaemia major patients and 50 normal individuals from Turkey, determining the relationship between the nucleotide variations in beta-globin gene cluster, the altered levels of foetal haemoglobin and the relative ratios of beta- and gamma mRNAs. We have found in beta-thalassaemia intermedia patients with high foetal haemoglobin expression that the three nucleotide variations in the 5' sequences of the gamma globin genes, A-->G at G gamma - 1396, the T-->C at A gamma - 228, and the GA-->AG at A gamma - 603/4, are linked to haplotype II in haplotypic homozygotes and the (AT)8N14(AT)7 motif in beta LCR. Conversely, the three single nucleotide substitutions in the 5' sequences of gamma globin genes, the G-->A at G gamma - 1225, the A-->G at A gamma + 25 and the C-->G at A gamma - 369, which have a strong linkage with haplotype I, V or VI in haplotypic homozygotes and the (AT)10N12(AT)12 and the (AT)9N12(AT)12 motifs in HS-2 of beta LCR are all associated with low foetal haemoglobin levels. The number of nucleotide changes in beta-globin gene cluster implied in our study are not the primary cause of the differences in haemoglobin F levels. They perhaps may contribute to the variations in the clinical severity observed among beta thalassaemia intermedia and major patients with other yet unknown gene conversions.

Cytogenetic study in 102 infertile men

Chromosomal anomalies may be a reason for male infertility. To find out whether this is true mitotic chromosome studies were performed on 41 males with azoospermia and 61 males with oligozoospermia. A constitutional chromosomal abnormality was diagnosed in 14 (34.1%) azoospermic patients and in 2 (3.3%) oligozoospermic patients. The 47,XXY karyotype was the commonest in the azoospermic group. An overall incidence of 15.7% abnormality indicates that routine chromosome analysis of infertile men should be considered.

Cytogenetic findings in thirty lung carcinoma patients

Primary tissue cultures of human lung tumors were prepared from 30 cases of which 16 were diagnosed as squamous cell carcinoma, six adenocarcinoma, four adenosquamous cell carcinoma, three large cell carcinoma, and one small cell lung carcinoma. Chromosomal abnormalities were observed in 26 cases by cytogenetic studies with a GTG banding technique. Specific chromosome bands frequently involved in structural abnormalities were seen on 1p11, 1q11, 2p10, 6p10, 7q11, 7q22, 7q32, 8q22, 9q22, 11q11, 21q10, and Xq24. We assumed that especially i(2)(p10), i(9)(p10), i(21)(q10), t(11;12), t(14;15), del(X)(q24), and loss of the Y chromosome may play a role in the development of lung cancer as secondary changes. In this way, our cytogenetic findings provide evidence that multiple genetic lesions are associated with the pathogenesis of lung cancer.

Normal phenotype with maternal isodisomy in a female with two isochromosomes: i(2p) and i(2q)

A 36-year-old normal healthy female was karyotyped because all of her five pregnancies had terminated in spontaneous abortions during the first 3 mo. Cytogenetic investigation disclosed a female karyotype with isochromosomes of 2p and 2q replacing the two normal chromosomes 2. Her husband and both of her parents had normal karyotypes. Molecular studies revealed maternal only inheritance for chromosome 2 markers. Reduction to homozygosity of all informative markers indicated that the isochromosomes derived from a single maternal chromosome 2. Except for the possibility of homozygosity for recessive mutations, maternal uniparental disomy 2 appears to have no adverse impact on the phenotype. Our data indicate that no maternally imprinted genes with major effect map to chromosome 2.

A somatic origin of homologous Robertsonian translocations and isochromosomes

One t(14q14q), three t(15q15q), two t(21q21q), and two t(22q22q) nonmosaic, apparently balanced, de novo Robertsonian translocation cases were investigated with polymorphic markers to establish the origin of the translocated chromosomes. Four cases had results indicative of an isochromosome: one t(14q14q) case with mild mental retardation and maternal uniparental disomy (UPD) for chromosome 14, one t(15q15q) case with the Prader-Willi syndrome and UPD(15), a phenotypically normal carrier of t(22q22q) with maternal UPD(22), and a phenotypically normal t(21q21q) case of paternal UPD(21). All UPD cases showed complete homozygosity throughout the involved chromosome, which is supportive of a postmeiotic origin. In the remaining four cases, maternal and paternal inheritance of the involved chromosome was found, which unambiguously implies a somatic origin. One t(15q15q) female had a child with a ring chromosome 15, which was also of probable postmeiotic origin as recombination between grandparental haplotypes had occurred prior to ring formation. UPD might be expected to result from de novo Robertsonian translocations of meiotic origin; however, all de novo homologous translocation cases, so far reported, with UPD of chromosomes 14, 15, 21, or 22 have been isochromosomes. These data provide the first direct evidence that nonmosaic Robertsonian translocations, as well as isochromosomes, are commonly the result of a mitotic exchange.

Monosomy 7 myelodysplasia in childhood. Two case reports

Monosomy 7 myelodysplasia is a rare hematological entity and is associated with morphological abnormalities in bone marrow and peripheral smear, and poor prognosis in children. We describe 2 children with infantile monosomy 7 myelodysplasia which evolved to leukemia. One of them died after 1 month, and the other is still on therapy for acute myelocytic leukemia (M4) which has evolved from chronic myelomonocytic leukemia. We concluded that chromosomal analysis must be done routinely in patients with myelodysplasia, in acute myeloid leukemia and chronic myelomonocytic leukemia.

Calcification of basal ganglia associated with pontine calcification in four cases: a radiologic and genetic study

We describe 4 brothers with calcification of basal ganglia, pons and dentate nuclei. An abnormal iron metabolism was found in one case. The radiological, pathogenetic and genetic aspects of this disease are discussed.

A case of juvenile chronic myeloid leukemia with XX/XXX mosaicism

Cytogenetic abnormalities are rarely found in patients with juvenile chronic myelogenous leukemia (JCML). In patients with chromosomal abnormalities, chromosomes 7 and 8 are usually involved. A case of JCML with 47 XXX and a 46 XX karyotype is described and the literature is reviewed. To our knowledge, this is the first case ever to have been reported.

Herpes simplex type 2 neutralization antibodies in patients with cancers of urinary bladder, prostate, and cervix

In the blood samples obtained from a total of 68 patients with cancers of the urinary bladder, prostate, and cervix, who applied to the Departments of Urology, Obstetrics, and Gynecology of Hacettepe Medical Faculty, neutralizing antibodies were sought for against herpes simplex type 2 by neutralization test. The same test was applied to 35 control patients with no known malignancies. In contrast to the presence of the antibody in 62.86% of the control subjects, this ratio was 90.70% in patients with cancer of the urinary bladder, 87.50% in those with prostatic carcinoma, and 88.89% in those with cancer of the cervix.

Selective chromosomal damage caused by human cytomegalovirus

The effect of human cytomegalovirus (CMV) on human foetal cell chromosomes was investigated. Cultures of foetal skin fibroblasts were infected with human CMV (AD-169 strain) and their chromosomes analysed at intervals. The distribution of chromosomal abnormalities was independent of chromosome length.