Sclerosteosis (craniotubular hyperostosis-syndactyly) with complex hyperphalangy of the index finger

Area of Science:

• Genetics
• Pediatrics
• Skeletal Dysplasias

Background:

• Sclerosteosis is a rare autosomal recessive disorder characterized by generalized thickening of the bones.
• It is caused by mutations in the SOST gene, which encodes sclerostin, a bone formation inhibitor.

Observation:

• A 4-year-old boy presented with bilateral, asymmetrical syndactyly of the index and middle fingers.
• He exhibited complex phalangeal anomalies, including hyperphalangy and hypoplasia with bracket epiphyses.
• Facial nerve palsy, hearing impairment, and generalized osteosclerosis developed between ages 3 and 4.

Findings:

• Genetic analysis revealed a homozygous SOST mutation in the patient.
• The identified SOST mutation is causative for sclerosteosis.

Implications:

• Bilateral syndactyly and abnormal finger patterning in children may be early indicators of sclerosteosis.
• This case highlights the importance of recognizing digital anomalies as potential prodromal signs of skeletal dysplasias.
• Early diagnosis of sclerosteosis can facilitate timely management and genetic counseling.