Digitotalar Dysmorphism

At a glance

Genetic disorder consisting of hand and foot deformities. It is characterized by flexion contractures of digits (congenital clasped thumbs, ulnar deviation of fingers), and the presence of “rocker-bottom” feet due to vertical talus anomalies.

Synonyms

Hereditary Ulnar Drift; Deviation de la main en Coup de Vent; Windblown Hand Deformity.

History

It was first described in a South African family of European descent in 1972.

Incidence

The exact incidence remains unknown. There are only few kindreds reported thus far in the literature.

Genetic inheritance

It is believed to be inherited as autosomal dominant trait with varying clinical expression. New evidence suggests a mutation in the exon nine of TNNT3 gene. The presence of the p.(Arg63His) mutation at position 63 of TNNT3 has been demonstrated through direct cycle sequencing of genomic DNA in six affected family members.

Pathophysiology

The deformities of the hand may, in part, be the result of abnormal flexor and extensor mechanisms and the absence of the lateral portion of the extensor tendons expansions. This abnormality could explain the soft tissue deficiency over the middle phalanges and the flexion deformity of the terminal phalanges. The intrinsic muscles may either be shortened or tight, atrophic, or even absent. The extensor tendons are often subluxed into the ulnar valleys between the metacarpal heads. In some individuals, the joint capsules may be involved. When present, the vertical talus is responsible for the “rocker bottom” aspect of the foot.

Clinical aspects

For some authors, this is a forme fruste of arthrogryposis multiplex congenita. However, the affection limited to hands and feet and its pattern of inheritance allow for differentiation from arthrogryposis multiplex congenita. Deformities of the hands and feet are present at birth and may progress over time. Constant features are flexion contractures of the metacarpophalangeal joints, ulnar deviation, and narrowing of the fingers. Adduction contraction of the thumb with soft tissue webbing to the palm limits the range of motion and is the most limiting disability of this disorder. In some cases, the other digits are flexed in all joints. Metacarpal synostosis is not uncommon. The palms are described as having only a single palmar crease and a very soft and shiny skin. The muscles of the shoulder girdle and the entire upper extremity may be underdeveloped with a limited range of motion. Although some patients have normal feet, bilateral vertical talus with “rocker bottom” feet is a frequent finding and could result in minor gait anomalies (“waddling”).

Anesthetic considerations

Careful positioning and padding of the hands are the only specific anesthetic considerations for this syndrome.

Other condition to be considered