Marked phenotypic variability in progressive diaphyseal dysplasia (Camurati–Engelmann disease): Report of a four‐generation pedigree, identification of a mutation in TGFB1, and review

Abstract

Progressive diaphyseal dysplasia (PDD) (Camurati–Engelmann disease) is an autosomal dominant craniotubular dysplasia characterized by hyperostosis and sclerosis of the diaphyses of the long bones and the skull. Mutations in transforming growth factor β‐1 (TGFB1) were recently found in patients with PDD. We report on a four‐generation pedigree with seven individuals affected by PDD, linkage and mutational analysis results, and review the literature. This pedigree demonstrates the autosomal dominant inheritance pattern, remarkable variation in expressivity, and reduced penetrance. The most severely affected individual had progression of mild skull hyperostosis to severe skull thickening and cranial nerve compression over 30 years. His carrier father remained asymptomatic into his ninth decade and had no radiographic hyperostosis or sclerosis of the bones. Symptomatic relatives presented with lower limb pain and weakness. They were initially diagnosed with a variety of other conditions. Two of the symptomatic individuals were treated successfully with prednisone. We genotyped 7 markers from chromosome region 19q13.1‐13.3 in 15 relatives and confirmed linkage to this region in this family. We screened the TGFB1 gene for mutations and identified a missense mutation resulting in an R218H substitution in the affected individuals, the asymptomatic obligate carrier, and another unaffected relative. We genotyped the family for seven known TGFB1 polymorphisms and a novel TAAA tetranucleotide repeat in intron 1. These polymorphisms did not appear to account for the variability in disease severity in this family. Our review illustrates how the disorder can significantly compromise health. Cranial involvement, which occurs in 61% of patients, can be severe, entrapping cranial nerves or causing increased intracranial pressure. Therapy with corticosteroids should be attempted in all symptomatic patients.