Camptodactyly: a 10-year series.

Camptodactyly is a non-traumatic, painless, non-neurogenic flexion deformity at the proximal interphalangeal joint of the little finger, which may occur in isolation or in various developmental dysmorphology syndromes. In a ten-year survey of almost 10,000 consecutive neurology outpatient referrals, using a passive case finding strategy, camptodactyly was observed with a frequency of 0.43%. All were cases of isolated camptodactyly, and all but one were asymptomatic. Camptodactyly was more often bilateral, often asymmetric, than unilateral. A family history was common, sometimes with intrafamilial heterogeneity (symmetry, degree of angulation). The pattern of inheritance was not certain, but the predominance of female cases (both directly observed and reported in families) and a paucity of father-to-daughter cases suggested the possibility of either sex-linked dominant transmission or mitochondrial DNA point mutation. There was no evidence for aminoaciduria or taurinuria, as previously reported in some cases. Hence, camptodactyly is relatively common as an incidental finding in patients referred to general neurological outpatient clinics, and thus possibly also in the general population. It is possible that camptodactyly is a heterogeneous disorder. Further studies are required to ascertain whether this is the case, and to probe further the inheritance and pathogenesis of the disorder.