Craniofacial, dental, and molecular features of Pyle disease in a South African child

INTRODUCTION: Pyle Disease (PD), or familial metaphyseal dysplasia [OMIM 265900], is a rare autosomal recessive condition leading to widened metaphyses of long bones and cortical bone thinning and genu valgum. We detail the oro-dental and molecular findings in a South African patient with PD. METHODS: The patient underwent clinical, radiographic and molecular examinations. An exfoliated tooth was analysed using scanning electron microscopy and was compared to a control tooth. RESULTS: The patient presented with marked Erlenmeyer-flask deformity (EFD) of the long bones and several Wormian bones. His dental development was delayed by approximately three years. The permanent molars were mesotaurodontic. The bones, including the jaws and cervical vertebrae, showed osteoporotic changes. The lamina dura was absent, and the neck of the condyle lacked normal constrictions. Ionic component analysis of the primary incisors found an absence of magnesium. Sanger sequencing revealed a novel putative pathogenic variant in intron 5 of SFRP4 (c.855+4delAGTA) in a homozygous state. CONCLUSION: This study has reported for the first time the implication of a mutation in the SFRP4 gene in an African patient presenting with PD and highlights the need for dental practitioners to be made aware of the features and management implications of PD.