Evidence for high-risk haplotypes and (CGG)n expansion in fragile X syndrome in the Hellenic population of Greece and Cyprus

Journal Article · Fri Jul 12 00:00:00 EDT 1996 · American Journal of Medical Genetics

DOI:https://doi.org/10.1002/(SICI)1096-8628(19960712)64:1<234::AID-AJMG42>3.0.CO;2-L· OSTI ID:476939

Syrrou, M; Georgiou, I; Pagoulatos, G ^[1]

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1. Univ. of Ioannina (Greece); and others

The expansion of the trinucleotide repeat (CGG){sub n} in successive generations through maternal meiosis is the cause of fragile X syndrome. Analysis of CA repeat polymorphisms flanking the FMR-1 gene provides evidence of a limited number of {open_quotes}founder{close_quotes} chromosomes and predisposing high-risk haplotypes related to the mutation. To investigate the origin of mutations in the fragile X syndrome in the Hellenic populations of Greece and Cyprus, we studied the alleles and haplotypes at DXS548 and FRAXAC2 loci of 16 independent fragile X and 70 normal control chromosomes. In addition, we studied 191 unrelated normal X chromosomes for the distribution and frequencies of CGG alleles. At DXS548, 6 alleles were found, 2 (194 and 196) of which were represented on fragile X chromosomes. At FRAXAC2, 6 alleles were found, 4 of which were present on fragile X chromosomes. Sixteen haplotypes were identified, but only 5 were present on fragile X chromosomes. The highest number of CGG repeats ({ge} 33) were associated with haplotypes 194-147, 194-151, 194-153, and 204-155. The data provide evidence for founder chromosomes and high-risk haplotypes in the Hellenic population. 20 refs., 3 figs., 2 tabs.

• OSTI ID: 476939
• Journal Information: American Journal of Medical Genetics, Vol. 64, Issue 1; Other Information: PBD: 12 Jul 1996
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
HUMAN X CHROMOSOME
CHROMOSOMAL ABERRATIONS
MEIOSIS
MENTAL DISORDERS
GENETICS
DISEASE INCIDENCE
RISK ASSESSMENT
PATIENTS
HEREDITARY DISEASES
GENES
GENE MUTATIONS
BIOLOGICAL EVOLUTION
MUTATION FREQUENCY
NUCLEOTIDES
METHYLATION
GREECE
CYPRUS
BIOLOGICAL MARKERS
POLYMERASE CHAIN REACTION
STATISTICS