Bone Abstracts

Introduction: In 1979 Sillence described Type II OI as perinatal lethal. We report two children whose features were consistent with Type II OI who survived beyond infancy. Both have mutations previously reported in cases of lethal OI.

Case 1: This girl was born full term, small for gestational age (SGA) following antenatal detection of short bowed femora. Skeletal survey showed multiple long bone fractures and a small chest with beaded ribs. A COL1A2 gene (c.1774 G>A in exon 31) mutation was identified. Following discharge at two weeks of age she was readmitted for respiratory infection, requiring long term non- invasive ventilation (NIV) from age five months. She developed raised intracranial pressure (ICP) due to basilar invagination, with hydrocephalus and cerebellar tonsillar herniation requiring ventriculo-peritoneal shunt insertion. At the current age of 2 years, she continues on NIV at home, has severe growth impairment (z scores: height −6.87, weight −4.63, head circumference −1.16).

Case 2: This boy was born full term SGA. Femoral bowing was demonstrated on antenatal ultrasound. Clinical and radiological features were similar to Case 1. He has a mutation in COL1A1 gene (c.3150_3158 dup in exon 44). He required ventilation from age 4 days and remains dependent on long term NIV. He developed raised ICP at four months due to bilateral subdural hematomas requiring subdural peritoneal shunt insertion. He was an in-patient until 11 months of age. At age 18 months he has severe growth impairment (z scores: height −9.81, weight −5.21, head circumference −1.61). Both children received two-monthly Pamidronate (0.75 mg/kg/day for two days) infusions, initiated in the first week of life. They received intensive support from the multidisciplinary OI team. Since discharge on NIV neither child was readmitted for significant respiratory infections. Both children have severe skeletal deformities and have had a single post natal long bone fracture. They have severe cognitive and motor delay and have not achieved head control yet.

Conclusions: The key determinants of survival in these children were respiratory support and neurosurgical intervention with multidisciplinary team support. Neurosurgical complications should be anticipated in this group and screening neuroimaging is advised.

Disclosure: The authors declared no competing interests.