Recurrent Fetal Anophthalmia Caused by retinoids acid gene 6 mutations: Correlation between prenatal ultrasonography, magnetic resonance imaging, and pathology.

Objective: Anophthalmia is an extreme form on the spectrum of anophthalmia-microphthalmia (A/M) syndrome. Most articles define fetal microphthalmia by an ocular diameter (OD) less than fifth percentile. Diagnosis of fetal microphthalmia using only orbital measurements such as interocular distance (IOD), and OD may neglect the presence or morphology of the fetal lens, hence failing to identify abnormalities of the fetal globe.

Case Report: We hereby present a case of isolated fetal anophthalmia in two consecutive pregnancies from the same mother. Both fetuses presented as full-sized globes with absence or small size of lens under fetal ultrasound examination. Magnetic resonance imaging and pathology of the second fetus further revealed a thorough view of the underdeveloped globes. Whole exon sequencing (WES) analysis for the parents-fetus trio revealed compound heterozygous mutations of the retinoids acid gene 6 (STRA6).

Conclusion: Detailed examination for intraocular structures including fetal lens, in addition to orbital measurements by ultrasound is crucial for diagnosis of diseases in the A/M spectrum.