PT  - JOURNAL ARTICLE
AU  - J Pearn
TI  - Incidence, prevalence, and gene frequency studies of chronic childhood spinal muscular atrophy.
AID  - 10.1136/jmg.15.6.409
DP  - 1978 Dec 01
TA  - Journal of Medical Genetics
PG  - 409--413
VI  - 15
IP  - 6
4099  - http://jmg.bmj.com/content/15/6/409.short
4100  - http://jmg.bmj.com/content/15/6/409.full
SO  - J Med Genet1978 Dec 01; 15
AB  - A total population study of chronic childhood spinal muscular atrophy (arrested Werdnig-Hoffmann disease, Kugelberg-Welander disease, SMA type II and III) was undertaken in north-east England to establish gene and carrier frequencies, incidence, and prevalence. The incidence of this disease was 1 in 24 100 live births. Prevalence was 1.20 per 100,000 of the general population. A technique for estimating an autosomal recessive gene frequency in the known presence of dominant new mutations (or phenocopies), using data from a segregation analysis, is described. Gene frequency was in the range (0.00451 to 0.00659 (95% confidence limits), with a working estimate of 0.0055. Carrier rates for the autosomal recessive gene concerned were 1 in 76 to 1 in 111 (95%) confidence limits), with a working estimate of 1 in 90 for genetic counselling purposes.