Absence of fragile X syndrome in Nova Scotia

The syndrome is characterised clinically by the triad of (1) long, narrow face with protruding chin and large ears, (2) macro-orchidism, and (3) mental retardation. 6 The molecular basis for the disease is usually an expanded triplet (CGG) repeat located in the 5[variant prime] region of the fragile...

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Bibliographic Details
Published in:Journal of medical genetics 2000-01, Vol.37 (1), p.77-79
Main Authors: BERESFORD, R G, TATLIDIL, C, RIDDELL, D C, WELCH, J P, LUDMAN, M D, NEUMANN, P E, GREER, W L
Format: Article
Language:English
Subjects:
Africa South of the Sahara - epidemiology
China - epidemiology
Europe - epidemiology
Families & family life
Females
Fragile X Mental Retardation Protein
Fragile X Syndrome - diagnosis
Fragile X Syndrome - epidemiology
Fragile X Syndrome - genetics
Gene expression
Humans
Institutionalization
Intellectual disabilities
Laboratories
Letters to the Editor
Male
Males
Medical research
Mutation
Nerve Tissue Proteins - genetics
Nova Scotia - epidemiology
Patients
Prevalence
RNA-Binding Proteins
Studies
United States - epidemiology
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Summary:The syndrome is characterised clinically by the triad of (1) long, narrow face with protruding chin and large ears, (2) macro-orchidism, and (3) mental retardation. 6 The molecular basis for the disease is usually an expanded triplet (CGG) repeat located in the 5[variant prime] region of the fragile X mental retardation (FMR1) gene. 7 8 In normal subjects, there are fewer than 60 copies of this CGG repeat; carrier females and transmitting males have a premutation that usually ranges from 60-200 repeats and in affected subjects the number is expanded to >200 copies. 7 The mutations are associated with absence or reduction in FMR1 gene expression. The absence of mutation in the samples with these large normal alleles was confirmed by Southern blotting using probe pE 5.1 and restriction enzymes EcoRI and BssHII. 8 The FMR1 CGG repeat size distribution in 1226 random alleles (470 males and 378 females) from Guthrie newborn screening samples (dried blood spots taken at birth) from the general Nova Scotia population was determined according to the methods of Carduci et al 24 and Fuet al. 7 They contained 36 different allele sizes ranging from seven to 55 repeats (fig 1 B).
ISSN:0022-2593
1468-6244
1468-6244
DOI:10.1136/jmg.37.1.77