Fetal Kabuki syndrome caused by a novel gene variation in KMT2D with primary carnitine deficiency: a case report.

BACKGROUND

Kabuki syndrome (KS) is an autosomal dominant syndrome involving multiple organs and systems and can be caused by mutation in KMT2D and KDM6A genes.

CASE REPORT: Here, we report the case of a pregnant woman who underwent prenatal family full-exon sequencing due to fetal multi-system abnormalities on ultrasound. Analysis revealed that the fetus had two rare congenital diseases: KS type 1 caused by mutation in the KMT2D and primary carnitine deficiency caused by mutation in the SLC22A5 gene, thus enriching our understanding of the prenatal ultrasound phenotype and gene mutation spectrum of KS. This case of fetal KS was caused by a novel frameshift mutation at the KMT2D gene locus c.14132_14133del which is not included in the ClinVar or Human Gene Mutation Database (HGMD) professional databases.

CONCLUSION

Prenatal ultrasound findings of KS are not unique, and the pathogenic genes associated with KS cannot be detected by conventional karyotype/microarray analyses. Consequently, the prenatal diagnosis of KS remains very difficult. However, whole-exome sequencing is recommended when multiple system abnormalities are present, routine testing is negative, and there is a high suspicion of a monogenic disorder. This strategy will identify fetal gene deletion or mutation early, allow informed genetic counselling, and help reduce the incidence of adverse pregnancy outcomes.