Camptodactyly 1

Description

Camptodactyly is defined as a permanent flexion contrature of 1 or both fifth fingers at the proximal interphalangeal joints. Additional fingers might be affected, but the little finger is always involved. Usually the condition appears to be sporadic in a family, but clinical examination of relatives reveals that it is an autosomal dominant condition subject to incomplete penetrance and variable expressivity (summary by Malik et al., 2008).

Clinical Features

In a rural area of western North Carolina, Murphy (1926) described camptodactyly in many members of 5 generations. Eleven of the affected persons also had knee-joint subluxation which was usually easily reduced.

Hefner (1929, 1941) reported its occurrence in 4 generations. Camptodactyly, though often occurring as an isolated anomaly, is occasionally a feature of genetically distinct disorders (see craniocarpotarsal dystrophy, 193700). Symptoms include streblodactyly, congenital contracture of fingers, and congenital Dupuytren contracture.

Parish et al. (1963) described flexion contractures of the fingers (streblodactyly: streblos = Gr. twisted, crooked) and amino aciduria in 10 females of 3 generations of a family. In 2 females the hands were normal but the same amino aciduria was present. Nine males were normal. Since all females in the direct line were affected by one or both of the traits mentioned, this is by definition hologynic. However, it is not, at least not necessarily, a sex-linked dominant as the authors proposed. In most patients fingers 2 to 5 were affected. This entity may not be different from camptodactyly.

Nevin et al. (1966) also found taurinuria in association with camptodactyly. The increased excretion of taurine seemed to be renal in origin. Taurine is not an amino acid but a sulfonated amine which arises as an end product of the metabolism of sulfur-containing amino acids. Several instances of male-to-male transmission were noted in the 4 families they studied.

Donofrio and Ayala (1983) reported a family in which 4 females in 2 generations were affected with the disorder reported by Parish et al. (1963) and called streblodactyly. No increase of abortions was noted in these families. The authors suggested sex-limited autosomal dominant inheritance. Streblodactyly is characterized by a permanent flexion contracture of all fingers at the proximal interphalangeal joints. Donofrio and Ayala (1983) suggested that camptodactyly (which often affects only the fifth finger and is clearly an autosomal dominant trait with incomplete penetrance) is distinct from streblodactyly.

Malik et al. (2008) studied a large 4-generation German family in which 13 members had camptodactyly segregating in an autosomal dominant fashion. Affected family members exhibited fifth finger camptodactyly associated with knuckle pads on the crooked fifth finger and on fingers 2 and 3. Women were usually more severely affected than men.

Mapping

In a large German family segregating autosomal dominant camptodactyly associated with knuckle pads, Malik et al. (2008) excluded 5 candidate loci known to be associated with camptodactyly-like phenotypes by microsatellite analysis. A subsequent genomewide scan showed linkage on chromosome 3q11.2-q13.12, with a maximum 2-point lod score of 3.04; recombination events defined a critical 14.94-cM (27.69-Mb) interval between markers D3S2465 and D3S3044. The authors designated the locus CAMPD1.