Long-term survival with diaphanospondylodysostosis (DSD): survival to 5 years and further phenotypic characteristics

We report on the natural history of diaphanospondylodysostosis (DSD) in the longest known survivor. DSD is a rare form of autosomal recessive vertebral dysotosis recently identified to be caused by a mutation in the BMPER gene. This condition is characterized by absent or severely delayed ossification of vertebral bodies, short broad thorax, short neck, protuberant abdomen, marked respiratory insufficiency, and normal appendicular skeleton. It is one of a number of spinal dysostoses, which are a heterogeneous group of axial skeletal malformations occurring during blastogenesis with continued evolution after birth. Significant medical intervention and at-home support contributed to the long-term survival of our patient. The patient had tracheomalacia, which resulted in respiratory insufficiency with thoracic insufficiency syndrome (TIS). Tracheostomy and vertical expandable prosthetic titanium rib (VEPTR) insertion operations ameliorated his symptoms. In addition, comprehensive physical and occupational therapy was performed due to chronic hypotonia. A consistent feature of all described DSD cases thus far are renal findings of dysplasia, nephrogenic rests or nephroblastomatosis, and/or cysts. The patient's renal cysts were monitored with serial ultrasounds at approximately 6-month intervals. The patient was diagnosed with bilateral renal cysts by ultrasound as a neonate, with eventual diagnosis at approximately 20 months of age with nephroblastoma suggesting this maybe an intrinsic part of DSD. The lack of other cases with nephroblastoma is likely related to the previously reported short period of survival.