Proportion of the GSTM1 0/0 genotype in some Slavic populations and its correlation with cystic fibrosis and some multifactorial diseases.

A homozygous gene deletion at the glutathione S-transferase M1 (GSTM1) locus of genomic DNA from blood spots was studied by PCR in the group of Slavic populations from the north-western and central-eastern regions of European Russia and in patients with lung cancer (LC), other tumors (OT), endometriosis (E), alcoholic cirrhosis (AC), cystic fibrosis (CF) and chronic bronchitis (CB). The frequencies of the GSTM1 0/0 genotype were 38.8% and 67.5% for both population groups, respectively. The proportion of the GSTM1 gene deletion genotype was estimated as significantly increased in LC (81%), OT (65%), E (81%), AC (77.3%), and in CB (73.6%) patients with symptoms of CB confirmed by X-ray but not in CB patients without X-ray evidence of disease (40.9%). A definite preponderance of GSTM1-0 homozygotes (51.1%) has been registered in CF patients of the pancreatic sufficient group with clear-cut pulmonological manifestations but not in those of the pancreatic insufficient group with predominantly intestinal or mixed clinical symptoms (41.2% and 37.5%, respectively). Earlier clinical manifestations and death before the age of 5 years are typical for GSTM1-deleted CF patients. These data support the notion that GSTM1 deletion should be considered as a convenient genetic marker for the early detection of groups at higher risk of many diseases caused by environmental and genetic factors, where manifestation depends on the lack of detoxification. High levels of GSTM1 0/0 genotypes in E patients favor the substantial contribution of certain environmental toxins in the pathogenesis of this widespread disease.

X;Y translocation in a girl with short stature and some features of Turner's syndrome: cytogenetic and molecular studies.

A 13 year old girl referred for chromosome analysis because of disproportionate short stature (short neck, curved legs, pectus excavatum) with an initial clinical diagnosis of Turner's syndrome was found to have the karyotype 46,X, + der(X) in 100% of her blood lymphocytes. By means of conventional differential staining (QFH/AcD, FPG, and RBA banding) supplemented with distamycin A treatment, the karyotype of the proband was interpreted as 46,X,t(X;Y) (p22.3;q11). The rearranged marker X chromosome was found to be active in 91% of lymphocytes studied. PCR analysis with Y chromosome specific oligoprimers showed the presence of some Y chromosome long arm DNA in both lymphocyte and gonadal tissue biopsy cells. At laparoscopy the patient was found to have small gonads with a rudimentary uterus and fallopian tubes. Histological examination of gonadal tissue showed primary follicles with dystrophic changes of the germ cells and numerous follicular cysts (polycystic ovaries). The proband's phenotype and its correlation with the genetic imbalance of the rearranged X chromosomes, as well as with non-random t(X;Y) chromosome inactivation, are briefly discussed.

Five years' experience of prenatal diagnosis of cystic fibrosis in the former U.S.S.R.

From a total of 490 cystic fibrosis (CF) high-risk families under supervision (mostly Russian Slavs from the European part of the country), DNA data including both direct screening for some CF gene (CFTR) mutations (delF508, G551D and 1677delTA) and allelic polymorphism studies with tightly CF linked DNA markers were collected from 261 families. All full families (129) and 86 CF families with a decreased index child were found to be either fully (42 per cent) or partially (40 per cent) informative for DNA analysis. Prenatal diagnosis (PD) was carried out in 161 CF families. Microvillar enzyme (MVE) assay was applied to all 140 PD at the second trimester either as a single test (88) or in conjunction with DNA analysis (52). The frequency of false-negative results of the MVE assay was 1.3 per cent and that of false-positive results, as judged by the albumin meconium test, was 5.0 per cent. Ambiguous results of MVE analysis were found in 30 cases, 12 of which were verified by DNA analysis. Molecular diagnosis of CF at the first trimester was carried out in 21 cases and four pregnancies were terminated. Altogether, 39 pregnancies with a predicted high risk of CF fetuses were terminated. The low average frequency of delF508 in CF chromosomes of Russian Slavs (50 per cent), its remarkable inter-population variation, and the significant proportion of at-risk families without an affected child determine the necessity of combined molecular and biochemical (MVE assay) approaches for efficient prenatal diagnosis of CF in the former U.S.S.R.