Apparent segregation distortion for the SOD1 mutation in amyotrophic lateral sclerosis
- Duke Univ. Medical Center, Durham, NC (United States)
- Northwestern Univ., Chicago, IL (United States); and others
Amyotrophic lateral sclerosis (ALS) is a devastating, progressive neurodegenerative disorder with a short duration form onset to death. Approximately 15% of all ALS cases are familial. Of this a subset of families ({approximately}20%) are caused by mutations in the SOD1 gene on chromosome 21. The recent identification of SOD1 as the causative factor in a subset of families has enabled us to classify at-risk as well as symptomatic SOD1 mutation carriers in completed sibships. Our investigations suggest that the transmission of the SOD1 mutation from parent to child occurs substantially more often than 50% of the time. At the present time we have examined this phenomena in 17 SOD1/ALS families with mutations in exons 1 (N=6 families), 2 (N=2), 4 (N=8) and 5 (N=1). In fully ascertained sibships from a mutation-carrying parent, there were 318 offspring available for mutation evaluation. Of these, 195 were found to have the SOD1 mutation, while 123 were without the mutation. These data result in a segregation ratio of 0.61 [chi-square = 16.3, P<0.0001]. Analysis of the individual exon mutation types indicated that the majority of the distortion was occurring in the exon 4 mutation families [chi-square=13.4, p<0.001 vs. non-4, chi-square=4.97, p<0.05]. These findings are of interest in light of the recent report of meiotic drive at the myotonic dystrophy locus, a CTG repeat expansion, variable onset, neurological disorder on chromosome 19. Additional SOD1/ALS mutation families are presently under study and these data will be similarily evaluated. Future studies include the genotyping of human sperm specimens for SOD1 mutation-bearing males. The possibility that over 66% of children of a mutation carrier could inherit the mutation preferentially would dramatically alter the counseling risk in such families. These studies provide further evidence of the occurrence of segregation distortion in humans.
- OSTI ID:
- 134306
- Report Number(s):
- CONF-941009-; ISSN 0002-9297; TRN: 95:005313-1039
- Journal Information:
- American Journal of Human Genetics, Vol. 55, Issue Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
Similar Records
Identification of new mutations in familial amyotrophic lateral sclerosis
Multimodal Synchrotron Radiation Microscopy of Intact Astrocytes from the hSOD1 G93A Rat Model of Amyotrophic Lateral Sclerosis