X-linked mental retardation: Linkage results in five unrelated families

Journal Article · Thu Sep 01 04:00:00 EDT 1994 · American Journal of Human Genetics

OSTI ID:134079

Moraine, C L; Dessay, B; Toutain, A ^[1]

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1. Centre Hospitalier et Universitaire Bretonneau, Tours (France); and others

X-linked mental retardations are a very common cause of mental deficiency in males. Combined clinical and linkage studies in great families can help to distinguish between particular pathologies in this very heterogenous group. In five unrelated families, we have assigned the corresponding genes to Xp22.2-p21.2 for family 1, Xp21.2-p11.21 for family 2, Xp11.4-p11.23 for family 3, Xq12 for family 4, and Xq28.5-pter for family 5, respectively. Clinical features were characterized by severe hypotonia with seizures and distinctive facies (family 1), hypotonia and hypoactivity with severe mental deficiency but absence of neurological signs (family 2), neonatal hypotonia with poor sucking and moderate intrauterine growth retardation (family 3), severe neonatal hypotonia with visual impairment and profound mental deficiency and seizures (family 4), and non-specific moderate mental deficiency (family 5). These results confirm the frequent gene localizations in Xq28 and in the pericentromeric region. But more precise clinical description of so-called non-specific X-linked mental retardations is necessary (especially for the natural history of mental deficiency) with the intention to associate several families in a unique linkage study. However, the recent description of different clinical patterns in three families with mutation in the L1CAM gene suggests that allelism may be more frequent than expected, that the real number of X-L.M.R. genes could be less important than previously reported, and that testing of candidate genes by mRNA or genomic DNA studies appears as a necessary step.

• OSTI ID: 134079
• Report Number(s): CONF-941009--
• Journal Information: American Journal of Human Genetics, Journal Name: American Journal of Human Genetics Journal Issue: Suppl.3 Vol. 55; ISSN AJHGAG; ISSN 0002-9297
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
BIOLOGICAL MARKERS
DOMINANT MUTATIONS
GENE MUTATIONS
GENES
GENETIC MAPPING
GENETICS
HEREDITARY DISEASES
HUMAN X CHROMOSOME
MALES
MENTAL DISORDERS
NERVOUS SYSTEM DISEASES
STATISTICS