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Title: Lack of expansion of triplet repeats in the FMR1, FRAXE, and FRAXF loci in male multiplex families with autism and pervasive developmental disorders

Abstract

Sib, twin, and family studies have shown that a genetic cause exists in many cases of autism, with a portion of cases associated with a fragile X chromosome. Three folate-sensitive fragile sites in the Xq27{r_arrow}Xq28 region have been cloned and found to have polymorphic trinucleotide repeats at the respective sites; these repeats are amplified and methylated in individuals who are positive for the different fragile sites. We have tested affected boys and their mothers from 19 families with two autistic/PDD boys for amplification and/or instability of the triplet repeats at these loci and concordance of inheritance of alleles by affected brothers. In all cases, the triplet repeat numbers were within the normal range, with no individuals having expanded or premutation-size alleles. For each locus, there was no evidence for an increased frequency of concordance, indicating that mutations within these genes are unlikely to be responsible for the autistic/PDD phenotypes in the affected boys. Thus, we think it is important to retest those autistic individuals who were cytogenetically positive for a fragile X chromosome, particularly cases where there is no family history of the fragile X syndrome, using the more accurate DNA-based testing procedures. 29 refs., 1 fig., 1 tab.

Authors:
;  [1];  [2]
  1. Queen`s Univ., Kingston (Canada)
  2. Ongwanada Resource Centre, Kingston (Canada) [and others
Publication Date:
OSTI Identifier:
478897
Resource Type:
Journal Article
Resource Relation:
Journal Name: American Journal of Medical Genetics; Journal Volume: 64; Journal Issue: 2; Other Information: PBD: 9 Aug 1996
Country of Publication:
United States
Language:
English
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; MENTAL DISORDERS; GENETICS; MALES; HEREDITARY DISEASES; BEHAVIOR; PHENOTYPE; GENES; GENE MUTATIONS; GENETIC MAPPING; HUMAN X CHROMOSOME; DNA-CLONING; NUCLEOTIDES; METHYLATION; GENE AMPLIFICATION; POLYMERASE CHAIN REACTION

Citation Formats

Holden, J.J.A., Julien-Inalsingh, C., and Wing, M. Lack of expansion of triplet repeats in the FMR1, FRAXE, and FRAXF loci in male multiplex families with autism and pervasive developmental disorders. United States: N. p., 1996. Web. doi:10.1002/(SICI)1096-8628(19960809)64:2<399::AID-AJMG33>3.0.CO;2-8.
Holden, J.J.A., Julien-Inalsingh, C., & Wing, M. Lack of expansion of triplet repeats in the FMR1, FRAXE, and FRAXF loci in male multiplex families with autism and pervasive developmental disorders. United States. doi:10.1002/(SICI)1096-8628(19960809)64:2<399::AID-AJMG33>3.0.CO;2-8.
Holden, J.J.A., Julien-Inalsingh, C., and Wing, M. Fri . "Lack of expansion of triplet repeats in the FMR1, FRAXE, and FRAXF loci in male multiplex families with autism and pervasive developmental disorders". United States. doi:10.1002/(SICI)1096-8628(19960809)64:2<399::AID-AJMG33>3.0.CO;2-8.
@article{osti_478897,
title = {Lack of expansion of triplet repeats in the FMR1, FRAXE, and FRAXF loci in male multiplex families with autism and pervasive developmental disorders},
author = {Holden, J.J.A. and Julien-Inalsingh, C. and Wing, M.},
abstractNote = {Sib, twin, and family studies have shown that a genetic cause exists in many cases of autism, with a portion of cases associated with a fragile X chromosome. Three folate-sensitive fragile sites in the Xq27{r_arrow}Xq28 region have been cloned and found to have polymorphic trinucleotide repeats at the respective sites; these repeats are amplified and methylated in individuals who are positive for the different fragile sites. We have tested affected boys and their mothers from 19 families with two autistic/PDD boys for amplification and/or instability of the triplet repeats at these loci and concordance of inheritance of alleles by affected brothers. In all cases, the triplet repeat numbers were within the normal range, with no individuals having expanded or premutation-size alleles. For each locus, there was no evidence for an increased frequency of concordance, indicating that mutations within these genes are unlikely to be responsible for the autistic/PDD phenotypes in the affected boys. Thus, we think it is important to retest those autistic individuals who were cytogenetically positive for a fragile X chromosome, particularly cases where there is no family history of the fragile X syndrome, using the more accurate DNA-based testing procedures. 29 refs., 1 fig., 1 tab.},
doi = {10.1002/(SICI)1096-8628(19960809)64:2<399::AID-AJMG33>3.0.CO;2-8},
journal = {American Journal of Medical Genetics},
number = 2,
volume = 64,
place = {United States},
year = {Fri Aug 09 00:00:00 EDT 1996},
month = {Fri Aug 09 00:00:00 EDT 1996}
}