Holoprosencephaly in identical twin neonates: An extremely rare case report

Abstract

Holoprosencephaly (HPE) is a rare congenital brain malformation which results from complete or incomplete separation of the forebrain and  diencephalon or horizontal separation of the optic and olfactory structures. The septum pellucidum is always absent and patients usually present  with gross facial abnormality. HPE has an incidence of 1 in 10,000-16,000 births. It is quite uncommon in twin gestations, and when it occurs, usually  only affects one of the twins. This study is however presenting the occurrence of HPE in presumably identical set of twins. The twins were a  product of assisted reproduction (IVF) and uneventful pregnancy: they were delivered preterm and of low birth weight. Twin one was microcephalic  and had facial hypoplasia, while twin two had an associated hydrocephalus. Both were hypoglycaemic. Chest radiographs and abdominal  ultrasound scans were normal. Echocardiography showed mid-muscular ventricular septal defect in twin two. Brain CT scans showed semi-lobar  holoprosencephaly in both twins, with hydrocephalus in twin two. This case report is being made to document an extremely rare occurrence of  holoprosencephaly in both identical twins who were products of assisted reproduction.