Epidemiology of septo-optic dysplasia with focus on prevalence and maternal age - A EUROCAT study

Septo-optic nerve dysplasia is a rare congenital anomaly with optic nerve hypoplasia, pituitary hormone deficienciesand midline developmental defects of the brain. The clinical findings are visual impairment, hypopituitarismand developmental delays. The aim of this study was to report prevalence, associated anomalies, maternal age and other epidemiological factors from a large European population based network of congenitalanomaly registries (EUROCAT). Data from 29 full member registries for the years 2005-2014 were included,covering 6.4 million births. There were 99 cases with a diagnosis of septo-optic dysplasia. The prevalence ofsepto-optic dysplasia in Europe was calculated to lie between 1.9 and 2.5 per 100,000 births after adjusting forpotential under-reporting in some registries. The prevalence was highest in babies of mothers aged 20-24 yearsof age and was significantly higher in UK registries compared with other EUROCAT registries (P=0.021 in themultilevel model) and the additional risk for younger mothers was significantly greater in the UK compared tothe rest of Europe (P=0.027). The majority of septo-optic dysplasia cases were classified as an isolated cerebralanomaly (N=76, 77%). Forty percent of diagnoses occurred in fetuses with a prenatal diagnosis. The anomalymay not be visible at birth, which is reflected in that 57% of the postnatal diagnoses occurred over 1 month afterbirth.This is the first population based study to describe the prevalence of septo-optic dysplasia in Europe. Septoopticdysplasia shares epidemiological patterns with gastroschisis and this strengthens the hypothesis of vasculardisruption being an aetiological factor for septo-optic dysplasia.