[A case of primary microcephaly associated with compound heterozygous variants of WDR62 gene].

Objective: To explore the genetic basis for a girl with primary microcephaly and growth retardation.

Methods: A girl who was admitted to Guangdong Maternal and Child Health Care Hospital in was selected as the study subject. Peripheral blood samples were collected from the child and her parents. Trio whole exome sequencing was carried out, and candidate variants were verified by Sanger sequencing and bioinformatic analysis. This study was approved by the Medical Ethnics Committee of Guangdong Maternal and Child Health Care Hospital (Ethics No. 202201278).

Results: DNA sequencing revealed that the child has harbored compound heterozygous variants of the WDR62 gene, including a frameshifting c.2963delC (p.Pro988Argfs*80) variant in exon 24 which was inherited from the unaffected father, and a nonsense c.3163G>T (p.Glu1055*) variant in exon 26, which was inherited from her unaffected mother. Both variants were predicted to affect the reading frame of the WDR62 gene.

Conclusion: Based on the clinical manifestations, results of genetic testing and pedigree analysis, the compound heterozygous variants were predicted to underlay the pathogenesis of microcephaly and growth retardation in this child. Above discovery has expanded the mutational spectrum for WDR62-associated Primary microcephaly type 2, and facilitated genetic counseling for the family.