We report a large genomic deletion of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, viz., a deletion that is frequently observed in Central and Eastern Europe. The mutation, termed CFTRdele2,3(21 kb), deletes 21,080 bp spanning introns 1-3 of the CFTR gene. Transcript analyses have revealed that this deletion results in the loss of exons 2 and 3 in epithelial CFTR mRNA, thereby producing a premature termination signal within exon 4. In order to develop a simple polymerase chain reaction assay for this allele, we defined the end-points of the deletion at the DNA sequence level. We next screened for this mutation in a representative set of European and European-derived populations. Some 197 CF patients, including seven homozygotes, bearing this mutation have been identified during the course of our study. Clinical evaluation of CFTRdele2,3(21 kb) homozygotes and a comparison of compound heterozygotes for deltaF508/CFTRdele2,3(21 kb) with pairwise-matched deltaF508 homozygotes indicate that this deletion represents a severe mutation associated with pancreatic insufficiency and early age at diagnosis. Current data show that the mutation is particularly common in Czech (6.4% of all CF chromosomes), Russian (5.2%), Belorussian (3.3%), Austrian (2.6%), German (1.5%), Polish (1.5%), Slovenian (1.5%), Ukrainian (1.2%), and Slovak patients (1.1%). It has also been found in Lithuania, Latvia, Macedonia and Greece and has sporadically been observed in Canada, USA, France, Spain, Turkey, and UK, but not in CF patients from Bulgaria, Croatia, Romania or Serbia. Haplotype analysis has identified the same extragenic CF-haplotype XV-2c/KM. 19 "A" and the same infrequent intragenic microsatellite haplotype 16-33-13 (IVS8CA-IVS 17bTA-IVS 17bCA) in all examined CFTRdele2,3(21 kb) chromosomes, suggesting a common origin for this deletion. We conclude that the 21-kb deletion is a frequent and severe CF mutation in populations of Eastern- and Western-Slavic descent.

Wide inter-individual variation of expression of compound metabolic enzymes is determined by polymorphism and may predispose the development of diseases provoked by environmental factors. The combined analysis of phase II detoxification system genes: arylamine N-acetyltransferase 2 (NAT2), and glutathione S-transferases (GST) M1 and T1 was carried out in patients with minimal/mild (group I; n = 36) and moderate/severe endometriosis (group II; n = 29) and controls (n = 72) of French origin, using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). The results show a significant difference between patients and controls with regard to NAT2 gene polymorphism (P < 0.05). This is mainly due to the high percentage of slow acetylator genotypes (SA) in patients compared with controls (60.0 versus 38.9%; P < 0.02) with a distinct preponderance in subjects with minimal/mild endometriosis (69.4%, P < 0.005) where there is a significantly elevated frequency of slow allele S1 (NAT2*5) (P = 0.05). Significantly increased proportions of GSTM1-deficient genotypes were found in both groups of patients, in comparison with the controls (75.0 and 79.3% versus 45.8%; P < 0. 0001). A preponderance of GSTT1-negative subjects among patients was also detected, but did not appear significant. We suggest the involvement of both NAT2 and GSTM1 detoxification system genes in the pathogenesis of endometriosis and the possible impact of NAT2 gene polymorphism in the development of different forms of this disease.

A homozygous gene deletion of the glutathione S-transferase M1 (GSTM1) locus of genomic DNA from blood spots was studied by the polymerase chain reaction in a group of French heavy smokers (n = 361), which included patients with severe chronic bronchitis (SCB; n = 87), moderate chronic bronchitis (MCB: n = 102) and hard smokers (HS) with no permanent clinical symptoms of chronic bronchitis (n = 172). The GSTM1 0/0 genotype was found in 71.3% and 65.7% of cases in SCB and MCB, respectively, compared with only 47.1% in the control HS group (P = 0.0002). This latter figure (47.1%) is consistent with the average GSTM1 deletion frequency in French Caucasians. Moreover, the results showed a significant difference in the distribution of the GSTM1 0/0 genotype for both the SCB and MCB groups against the control HS group, according to gender (SCB: P = 0.001; MCB: P = 0.005), age (SCB: P = 0.0001; MCB: P = 0.005) and smoking history (SCB: P = 0.0001; MCB: P = 0.005). Thus, individuals homozygous for the GSTM1 gene deletion, especially in the under-41 age group (SCB: P = 0.001; MSB: P = 0.04) with an average smoking history of 16-30 pack-years (SCB: P = 0.002; MSB: P = 0.01) are more prone to chronic lung diseases, such as SCB and MCB, than are GSTM1 +/+ or 0/+ subjects. Population screening of young people for the identification of GSTM1 0/0 subjects, with special emphasis on smoking habits, might be useful (1) for the early detection of individuals at high risk of lung complications caused by environmental toxins and pollutants and (2) in clinical practice, in order to prevent the development of chronic bronchitis, which is a common disease.

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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.