Bone Abstracts

Objectives: To describe two familiar cases of Hajdu–Cheney syndrome, a rare genetic disorder associated with skeletal dysplasia, craniofacial abnormalities, short stature, acro-osteolysis and osteoporosis.

Materials and methods: A 51-year-old woman (case 1) presented in our outpatient clinic with pseudo-clubbing of some fingers and toes. She was short (139 cm) and thin (34 kg). She had facial and cranial abnormalities: thin lips, long philtrum, full cheeks, micrognathia, short neck, bushy eyebrows and coarse hair. Upon palpation, open skull sutures were noted. Her 21-year-old daughter (case 2) was also observed and showed similar facial and cranial abnormalities with short stature (141 cm) and low weight (31 kg).

Results: Investigation in case 1 revealed: radiographs with acro-osteolysis of some distal phalanges in fingers and toes, persistence of skull sutures and enlargement of the sella turcica. Bone densitometry with dual-energy X-ray absortiometry (Lunar Expert): T-score of −4 in lumbar spine (L1–L4) and a T-score of −2 in total hip and femoral neck. Blood and urinary test s revealed high β-crosslaps and low vitamin D levels, without further abnormalities. Investigation in case 2 revealed: radiographs with persistence of skull sutures and enlargement of the sella turcica. Bone densitometry with dual-energy X-ray absortiometry (Lunar Expert): T-score of −2.3 in lumbar spine (L1–L4) and a T-score of −1.1 in total hip and femoral neck. Blood and urinary tests revealed high beta-crosslaps and very low vitamin D levels, without further abnormalities.

Conclusion: Based on clinical, radiologic and laboratory findings, Hajdu–Cheney syndrome was diagnosed in both cases. Recently, it was found that mutations in the NOTCH2 gene are responsible for the syndrome. The majority of the reported cases are sporadic although a genetic background with an autosomal dominant pattern of transmission has been reported. Our cases further support the syndrome’s inheritable pattern.