Bone Abstracts

Background: Genetic advances have led to the identification of 14 genes implicated in Osteogenesis imperfecta [OI], encompassing 96–98% of cases. Hallmark features of osteogenesis imperfecta include fractures from minimal trauma, bowing of the legs and growth retardation. Non-skeletal features include blue sclera, dentinogenesis imperfecta, hearing and refractory visual deficits, pulmonary dysfunction and cardiac valvular malformations. Classical radiographic features are that of generalized osteopenia, fractures and wormian skull bones.

Presenting Problem: The proband is the second child of non-consanguineous parents, referred to our service at 10 months with a history of multiple fractures from minimal trauma. She was delivered by LSCS for low-lying placenta and breech presentation at term. Birth weight was 1.95 kg. Fractures were noted from Day 3 of life affecting other femurs and tibiae. A skeletal survey was carried out at 5 months and confirmed multiple wormian skull bones, flattened thoracic vertebrae and bilateral coxa valga. In addition, she has required an atrial septal defect repair and ongoing feed-aspiration. Hearing and vision are normal, with dental review pending. She has marked global development delay and is unable to sit unsupported at 15 months and unable to grab objects. The family history is negative for fractures or early osteoporosis but there is strong history of multiple miscarriages of unknown cause.

Clinical management: She is receiving ongoing multidisciplinary management including endocrinology, general paediatrics, specialist physiotherapy, dental and ophthalmology review. Extended genetic panel for collagen gene analysis has not yielded a pathogenic mutation and microarray is normal. No active medical treatment has been initiated as she has not incurred any further fracture since referral. Recent MRI brain scan has shown polymicrogyria of unknown origin which would explain her profound developmental delay.

Discussion: Although next generation sequencing has identified the majority of genes implicated in the pathogenesis of early primary osteoporosis, there remain a small number of unsolved cases. This proband meets the clinical criteria for a diagnosis of osteogenesis imperfecta and would have been expected to display an abnormality in collagen gene sequencing but she has eluded genetic diagnosis. To date there are no published links between polymicrogyria and osteogenesis imperfecta.

Disclosure: The authors declared no competing interests.