Brachydactyly type B: case report and further evidence for clinical heterogeneity

We present a male child with digital and radiographic findings consistent with brachydactyly type B. His left hand had 2-4 syndactyly, shortened first and fifth digits and single palmar and fifth finger flexion creases. The nail on the second finger was hypoplastic. The right hand had a small thumb and curving of the second finger towards the midline. The left foot had a short left hallux with an absent nail, 2-4 syndactyly and an absent toe. His right foot had a short, dorsiflexed hallux with a hypoplastic nail, 2-3 syndactyly and an overlapping toe. Radiographs showed asymmetrical hypoplasia of the middle and terminal phalanges and there were no extra-articular findings to suggest Sorsby syndrome. Brachydactyly type B has classically been described as hypoplasia or absence of the terminal phalanges with absent nails. Although other digital anomalies have previously been described with brachydactyly type B, the absent digit, atypical syndactyly and marked asymmetry in this child make this case a good illustration of the clinical heterogeneity that can be associated with this type of brachdactyly. We provide a brief review of syndromes in which similar digital malformations have been reported.