RT Journal Article SR Electronic T1 Segregation analysis of peripheral neurofibromatosis (NF1). JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 307 OP 310 DO 10.1136/jmg.27.5.307 VO 27 IS 5 A1 M Littler A1 N E Morton YR 1990 UL http://jmg.bmj.com/content/27/5/307.abstract AB Four studies of NF1 support a prevalence of 0.0003 and a carrier incidence at birth of 0.0004. The gene frequency (q) is therefore 0.0002, and the proportion of cases owing to fresh mutation is 0.56. The mutation rate (xq) is 10(-4), an unusually high value suggestive of a large gene. Penetrance among subjects examined is virtually complete, and there is no evidence of phenocopies or somatic mutations.