How many X-linked genes for non-specific mental retardation (MRX) are there?

Journal Article · Fri Jul 12 04:00:00 EDT 1996 · American Journal of Medical Genetics

DOI:https://doi.org/10.1002/(SICI)1096-8628(19960712)64:1<158::AID-AJMG26>3.3.CO;2-V· OSTI ID:476926

Gedeon, A K; Donnelly, A J; Mulley, J C ^[1]

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1. and others

X-linked mental retardation (XLMR) is that proportion of mental retardation (MR) showing the distinctive pattern of inheritance associated with the X chromosome. XLMR is subdivided into syndromal and non-specific (MRX) forms. MRX is clinically homogeneous but genetically heterogeneous. Affected males in families segregating MRX have no consistent phenotypic expression apart from their MR to distinguish them from unaffected males or affected males in other MRX families. Syndromal MRs have additional neurological or phenotypic characteristics that define a syndrome, and most of these syndromes are rare. Within some families an affected male may show {open_quotes}soft{close_quotes} syndromal signs, but where this is not evident in other affected males from the same family, the MR is diagnosed as non-specific. Delineation from fragile X syndrome or FRAXE MR can now be confidently made with the aid of direct molecular tests which detect the (CCG){sub n} expansion at either FRAXA or FRAXE. MRX can be expressed in carrier females but with milder manifestations. The gene in such cases could be partially dominant or result from a skewed X-inactivation pattern in neural tissue. 39 refs., 1 fig., 1 tab.

• OSTI ID: 476926
• Journal Information: American Journal of Medical Genetics, Journal Name: American Journal of Medical Genetics Journal Issue: 1 Vol. 64; ISSN 0148-7299; ISSN AJMGDA
• Country of Publication: United States
• Language: English

Related Subjects

55 BIOLOGY AND MEDICINE
BASIC STUDIES
BIOLOGICAL MARKERS
CHROMOSOMAL ABERRATIONS
DNA SEQUENCING
DNA-CLONING
GENE MUTATIONS
GENE RECOMBINATION
GENES
GENETIC MAPPING
GENETICS
HEREDITARY DISEASES
HUMAN X CHROMOSOME
MALES
MEIOSIS
MENTAL DISORDERS
NUCLEOTIDES
PHENOTYPE
POLYMERASE CHAIN REACTION
RESOLUTION
REVIEWS
STATISTICS