Objective: To explore the genetic etiology for a fetus with Walker-Warburg syndrome(WWS).
Methods: A fetus with WWS diagnosed at Gansu Provincial Maternity and Child Health Care Hospital in June 9, 2021 was selected as the study subject. Genomic DNA was extracted from amniotic fluid sample of the fetus and peripheral blood samples from its parents. Trio-Whole exome sequencing (trio-WES) was carried out. Candidate variants were verified by Sanger sequencing.
Results: The fetus was found to harbor compound heterozygous variants of the POMT2 gene, namely c.471delC (p.F158Lfs*42) and c.1975C>T (p.R659W), which were respectively inherited from its father and mother. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), they were respectively rated as pathogenic (PVS1+PM2_Supporting+PP4) and likely pathogenic (PM2_Supporting+PM3+PP3_Moderate+PP4).
Conclusion: Trio-WES may be used for the prenatal diagnosis of WWS. The compound heterozygous variants of the POMT2 gene probably underlay the disorder in this fetus. Above finding has expanded the mutational spectrum of the POMT2 gene and enabled definite diagnosis and genetic counseling for the family.