Lower motor neuron degeneration and familial predisposition to colonic neoplasia in two adult siblings.

A previously unreported association between a familial predisposition to colonic neoplasia and familial adult onset lower motor neuron (LMN) degeneration is reported. Two brothers presented at the ages of 53 and 44 years with multiple colonic adenomata and invasive colonic carcinoma respectively. Subsequently both developed a virtually identical pattern of motor neuron disease of progressive muscular atrophy type. At presentation both had LMN weakness affecting predominantly the upper limb and neck muscles. The disease progressed rapidly to involve the lower limb and bulbar musculature and both brothers died after a 15 month course. Necropsy was performed on one brother and showed pathological changes confined to the LMNs with no evidence of involvement of the pyramidal tracts or motor cortex. The combination of these diseases in two brothers may be of importance in the search for genes responsible for familial motor neuron disorders. It is suggested that a genomic search should be directed initially to the vicinity of known colon neoplasia genes, particularly 5q, 17q and 18q.