Követelem Jeszenszky Géza lemondatását

irodalomkutató

/ #18 a rokonházasság---'consanguineous marriage'---további veszélyei

2012-10-31 07:56

J Med Genet. 1999 Apr;36(4):290-294.
Identification of a single ancestral CYP1B1 mutation in Slovak Gypsies (Roms) affected with primary congenital glaucoma.
Plásilová M, Stoilov I, Sarfarazi M, Kádasi L, Feráková E, Ferák V.
Department of Molecular Biology, Comenius University, Bratislava, Slovakia.
Abstract
Primary congenital glaucoma (PCG) is an autosomal recessive eye disease that occurs at an unusually high frequency in the ethnic isolate of Roms (Gypsies) in Slovakia. Recently, we linked the disease in this population to the GLC3A locus on 2p21. At this locus, mutations in the cytochrome P4501B1 (CYP1B1) gene have been identified as a molecular basis for this condition. Here, we report the results of CYP1B1 mutation screening of 43 PCG patients from 26 Slovak Rom families. A homozygous G-->A transition at nucleotide 1505 in the highly conserved region of exon 3 was detected in all families. This mutation results in the E387K substitution, which affects the conserved K helix region of the cytochrome P450 molecule. Determination of the CYP1B1 polymorphic background showed a common DNA haplotype in all patients, thus indicating that the E387K mutation in Roms has originated from a single ancestral mutational event. The Slovak Roms represent the first population in which PCG is found to result from a single mutation in the CYP1B1 gene, so that a founder effect is the most plausible explanation of its increased incidence. An ARMS-PCR assay has been developed for fast detection of this mutation, thus allowing direct DNA based prenatal diagnosis as well as gene carrier detection in this particular population. Screening of 158 healthy Roms identified 17 (10.8%) mutation carriers, indicating that the frequency of PCG in this population may be even higher than originally estimated.
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The majority of Roms still preserve their language, traditions, and lifestyle, and their communities remain almost totally genetically isolated not only from the surrounding population but also from one another. Endogamy is a strict rule, consanguineous marriages are frequent (15-45%), and the inbreeding coefficient ranges among the highest world wide. This typical Gypsy founder demography, history, and population structure is likely to be responsible also for the increased incidence of other autosomal recessive diseases in different European Rom communities.