Introduction

Tay-Sachs disease (TSD) is a rare autosomal recessive lysosomal storage disorder caused by mutations in the HEXA gene that encodes the alpha-subunit of the lysosomal enzyme β-hexosaminidase A (Hex A).

Case Presentation

The case presented is of a 19-week pregnant 30-years-old female with a bad obstetric history. Her two previous female children expired at 11 months and 5 years of age, respectively, with suspected metabolic or neurodegenerative disorders. The third female child presented at 4 years of age with a history of seizures and global developmental delay, and had facial dysmorphism and macrocephaly. Looking at the past obstetric history and history of consanguinity, whole-exome sequencing (WES) of both parents and Sanger sequencing of the fetus was carried out.

Conclusions

Whole-exome sequencing of parents and prenatal genetic testing revealed one pathogenic mutation, NM_000520.6(HEXA):c.1274_1277dup (p.Tyr427fs), in the HEXA gene in this family. The parents were heterozygous, while the fetus was homozygous for this mutation, which manifests in Tay-Sachs disease.