Fetal Anemia and Periventricular Hyperechogenicity/Halo as a Prenatal Indicator of <i>CoQ10</i> Deficiency Associated With Biallelic Variant in <i>COQ2</i> Gene

Coenzyme Q10 (CoQ10) is crucial for mitochondrial function, and its deficiency leads to diverse clinical manifestations. Prenatal phenotypes are rarely described, with no prior reports of fetal anemia. We present a case of a 24-year-old primigravida at 28 + 2 weeks gestation with elevated fetal middle cerebral artery peak systolic velocity indicating anemia. Neurosonography revealed bilateral periventricular hyperechogenicity/ halo. Fetal blood sampling confirmed anemia, and exome sequencing identified biallelic likely pathogenic COQ2 variants, confirming CoQ10 deficiency. This case highlights the crucial role of detailed ultrasound and neurosonography in identifying findings like fetal anemia and periventricular hyperechogenicity in the third trimester, aiding in diagnosis of rare conditions such as CoQ10 deficiency. Fetal anemia, typically linked to immunological causes, is presented here for the first time as a prenatal phenotype of CoQ10 deficiency, emphasizing the importance of considering genetic factors in non-immune settings.