Split-hand/foot malformation (SHFM), also known as ectrodactyly, is a highly heterogeneous congenital limb-development defect due to the absence of central rays of the autopod and varying degrees of fusion of the remaining digits. SHFM has a prevalence of 1:10,000-1:90,000 worldwide. It can occur as an isolated malformation or in combination with other anomalies. Split-hand/foot malformation 1 with sensorineural hearing (SHFM1D) loss is extremely rare reported in a few families and characterized clinically by split hand/split foot malformation and mild to moderate sensorineural hearing loss, sometimes associated with mental retardation, ectodermal and craniofacial findings, and orofacialclefting.
SHFM1D exhibits autosomal recessive inheritance. It is associated with mutations in the DLX5 gene, which is involved in bone development and fracture healing.
See: [Yemen > Shamseldin et al., 2012]
Shamseldin et al. (2012) performed autozygome analysis and exome sequencing to study a Yemeni consanguineous family with autosomal recessive split hand and foot malformation in Saudi Arabia. The first patient was a 6 year old girl, who had severe limb defects noted at birth. She suffered from hearing loss. She had mild synophrys and low anterior hair line. There was dorsalisation of the palms, tapered fingers and circumferential nails, and asymmetric short and severely deformed legs and feet. There was mild scoliosis as well as restriction of joint flexion at all the metacarpophalangeal and interphalangeal joints. The parents were first cousins and had two affected children and several other affected relatives. One of the affected children died at the age of 7 years. The second 4 year old girl also suffered from hearing loss. She had mild frontal bossing and high frontal hair line, severe asymmetric claw-like deformity. The right hand had an elongated ebducted thumb, wide fused ring and middle fingers, and an absent index finger. A novel missense mutation was identified in the DLX5 gene in all affected members.