Brachydactyly is a common feature of congenital hand anomalies characterized by shortening of the phalanges and/or metacarpals. Mutation of growth differentiation factor-5 (GDF5) may result in loss of appearance and function in brachydactyly type C (BDC). Herein, we describe an 11 year-old Chinese BDC patient with significant shortening of the 1st, 2nd, 3rd, and 5th digits. Notably, according to the analysis of metacarpophalangeal pattern profiles, we do not think the 4th digit appears unaffected as usual. In this patient a novel heterozygous frameshift mutation was identified (c.349delG) causing termination of translation after translating six amino acids from codon 117 (p.A117fs*6). This mutation is located in the propeptide region of GDF5, causing GDF5 haploinsufficiency in BDC. Considering our results expanding the genetic spectrum of BDC-causing mutations, further molecular analysis to diagnose and reclassify isolated brachydactyly on the basis of genotype rather than phenotype is warranted.

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Background: Pollicization remains the default treatment for severe thumb hypoplasia, while the metatarsal transfer is an effective choice for metacarpal reconstruction, with competitive outcome of reconstructed thumb. However, rare researches focused on the outcome of donor foot of the metatarsal transfer. The purpose of this study was to evaluate the short-term outcome of donor foot after full-width metatarsal transfer for Manske Type IIIB and IV thumb hypoplasia.Methods: Fourteen patients with Manske Type IIIB and IV thumb hypoplasia were enrolled in the study. A full-width metatarsal graft (vascularised, from the second metatarsal or non-vascularised, from the fourth metatarsal) was harvested; an adjacent half-width graft from the third metatarsal was transposed horizontally to replace the donor defect. Objective and subjective evaluations were performed at least 12 months postoperatively. The appearances of the toes and the radiographic findings of the metatarsals were evaluated by two authors, the length and width of the metatarsals were measured on digital anteroposterior radiographs using a paired sample t test. The parental satisfaction was evaluated using a self-administered questionnaire. Results: Among these 14 patients (eight type ⅢB and six type Ⅳ thumbs), there were ten male and four female patients. The mean age at operation was 34.2 months (range: 14 to 127 months), and the mean follow-up was 16.1 months (range: 12 to 30 months). Toe lengthening, toe overriding, and synostosis between the metatarsals were observed in two, two and two patients; toe shortening, toe deviation, metatarsal lengthening and metatarsal angulation were observed in one, one, one and one patient. The lengths of third and fourth metatarsals in donor site were significantly larger than those in contralateral side, while the widths of third and fourth metatarsals were not significantly different between donor and contralateral sides. The mean score in the parental satisfaction questionnaire (full score, 30) was 27.2, (range: 17 to 30), which rated as “good”. Conclusions: Following full-width metatarsal transfer for Type IIIB and IV thumb hypoplasia, transposition of the adjacent half-width metatarsal for donor reconstruction results in minor donor deficit and overall parenteral satisfaction. Level of evidence: Ⅳ