Diagnosis of inborn errors of metabolism through prenatal exome sequencing with targeted analysis for fetal structural anomalies

Over a 30-month period testing of 921 pregnancies resulted in a genetic diagnosis in 32.8% of cases (302/921). Here we review cases diagnosed with an inborn error of metabolism. Diagnoses of inborn errors of metabolism (IEM) were classified according to the ICIMD classification system. Genetic diagnoses were assessed against Human Phenotype Ontology terms, gestation of scan findings and literature evidence. 35/302 diagnoses (11.6%) represented IEM. Almost half affected metabolism of complex macromolecules and organelles (n = 16), including congenital disorders of glycosylation (n = 8), peroxisome biogenesis disorders (n = 4), and lysosomal storage disorders (n = 4).