Calvarial doughnut lesions and osteoporosis: a new three-generation family and review

Familial calvarial doughnut lesions (CDLs; OMIM 126550) is a rare autosomal dominant low bone density disorder characterized by distinctive X-ray translucencies of the skull, multiple fractures, elevated serum Alkaline Phosphatase, and dental caries. Only three families comprising 22 cases and 29 sporadic cases with the disorder have been reported. We describe a three-generation family consisting of three cases with clinical, radiological, biochemical, and histological findings consistent with this condition. All affected family members presented with childhood onset primary osteoporosis and typical CDLs or hyperostosis of the skull. In addition, the youngest family member was diagnosed with congenital glaucoma and her paternal grandmother with chronic congestive glaucoma. Glaucoma has not been previously described in this disorder. Adult patients also had recurrent cranial nerve palsies. No pathogenic mutations in the genes encoding low density lipoprotein receptor-related protein 5 (LRP5) or type I collagen (COL1A1 or COL1A2) were identified, suggesting that the disorder is caused by another dominant, yet unidentified gene. The literature is reviewed.