Craniofacial growth in Mulibrey nanism and impact of growth hormone treatment

Abstract Background Mulibrey nanism (MUL) impacts cellular metabolism and leads to severe prenatal onset growth restriction, distinctive craniofacial features, heart disease, hypogonadism, and predisposition to tumors. Growth hormone therapy is commonly used in treatment of patients with MUL. The aim of this study was to characterize craniofacial features and the effects of growth hormone on craniofacial growth and dental development in individuals with MUL by comparing radiographs of individuals with and without growth hormone therapy during growth. Methods Cephalometric measurements were analysed for 17 angular and linear variables on lateral skull radiographs of 34 individuals aged from 4 to 49 years with MUL to assess the anterior skull base angulation, antero-posterior and vertical position of the maxilla, mandible, and dentition. Dental age was estimated from 16 panoramic radiographs. The findings of those treated with growth hormone (71%), with treatment initiation between 2 to 9 years of age, were compared with those without growth hormone therapy and with normal population references. Results Most of the cephalometric measurements were smaller in individuals with MUL compared to normal population. The antero-posterior position of both jaws and the posterior facial height were more than two standard deviations below the population norm. Conclusions The small dimensions persisted in patients with growth hormone therapy apart from antero-posterior position of the upper jaw, which was slightly less retruded in individuals with growth hormone therapy compared to those without. Development of the permanent dentition did not associate with growth hormone therapy.