Cause:Genetic, autosomal dominant or sporadic mutations in germline cells (Nejm 1994;331:1403); mutation on long arm of chromosome 17
Pathophys: (Ann IM 2006;144:842)
Sx:Onset by age 5 yr, variable depending on site of lesions
Si:
Café-au-lait spots (90%); 6 spots, >1.5 cm in adults, or >0.5 cm in prepubertal patients (Peds 1992;90:924; J Peds 1990;116:845); axillary or inguinal or inguinal "freckles" (Crowe sign) are the same thing; "coast of California" smooth edges unlike "coast of Maine" edges of Albright's syndrome(bone cysts and fibrous dysplasia, precocious puberty) (rx'd with testolactoneNejm 1986;315:1115)
Neurofibromas: soft skin nodules; plexiform neurofibromas are subcutaneous nodules along nerve course; also present internally, especially in bone and CNS
Lisch nodules, dome-shaped pigmented hamartomas on iris; present in 100% by age 20 yr (Nejm 1991;324:1264)