Segregation analysis of 1885 DMD families: significant departure from the expected proportion of sporadic cases.
The proportion of sporadic cases of Duchenne muscular dystrophy has been estimated by classical segregation analysis in a pooled sample of 1885 sibships from 7 different countries. A significant departure from the theoretical expectations based on mutation-selection equilibrium is observed (segregation frequency = 0.439 +/- 0.017; frequency of sporadic cases = 0.229 +/- 0.026, at the maximum likelihood). The occurrence of germinal mosaicism in some of the mothers of Duchenne cases may account for this peculiar finding, although a possible role of inequality of mutation rates in the two sexes cannot be ruled out.
Barbujani
G
G
Dipartimento di Biologia, Università di Padova, Italy.
Russo
A
A
Danieli
G A
GA
Spiegler
A W
AW
Borkowska
J
J
Petrusewicz
I H
IH
D002877:Chromosomes, Human; D005260:Female; D006801:Humans; D008297:Male; D009030:Mosaicism / Q000235:genetics; D009136:Muscular Dystrophies / Q000453:epidemiology / Q000235:genetics*; D009154:Mutation; D011336:Probability; D012641:Selection, Genetic; D013223:Statistics as Topic