[Clinical characteristics and genetic analysis of a case of infantile Schaaf-Yang syndrome due to a heterozygous variant of MAGEL2 gene].

OBJECTIVE

To explore the diagnosis, treatment and genetic analysis of an infant with Schaaf-Yang syndrome (SYS).

METHODS

An infant suspected for SYS at the Hunan Provincial Children's Hospital on June 10, 2022 was subjected to trio-whole exome sequencing, and Sanger sequencing was used to verify the candidate variant. Structure of the wild-type and mutant proteins was constructed to analyze the potential hazard.

RESULTS

The infant was found to harbor a heterozygous frameshifting variant of c.1908delG (p.R637Gfs*65) of the MAGEL2 gene, which was found in neither of his parents. The variant has not been recorded by the public databases, and no relevant literature was retrieved. As the result of the variant, the MAGEL2 protein only retained part of its proline domain, which may lead to destruction and/or down-regulation of its function.

CONCLUSION

The c.1908delG (p.R637Gfs*65) variant of the MAGEL2 gene probably underlay the pathogenesis in this child. Combined with his clinical characteristics, the child was diagnosed with SYS. Above finding has also enriched the mutational spectrum of the MAGEL2 gene.