[Analysis of clinical features and genetic variant in a neonate with Au-Kline syndrome due to a de novo variant of the HNRNPK gene].

OBJECTIVE

To explore the clinical phenotype and genetic basis of a neonate with Au-Kline syndrome (AKS).

METHODS

Clinical data and result of genetic testing of a neonate with AKS who was admitted to the Affiliated Provincial Children's Hospital of Anhui Medical University in January 2021 were retrospectively analyzed. Relevant literature was searched from the Wanfang Data Knowledge Service Platform, China National Knowledge Infrastructure and PubMed databases using key words "Au Kline syndrome", "Au-Kline syndrome", "HNRNPK" and "AKS". The research period was set as from January 1, 2000 to December 31, 2020.

RESULTS

The male newborn has manifested feeding difficulties, hypotonia, absence of the upper jaw to the uvula and facial dysmorphism. Trio-whole exome sequencing revealed that he has harbored a frameshift c.478dupA (p.Ile160AsnfsTer7) variant of the HNRNPK gene, which was varified by Sanger sequencing to have a de novo origin. The variant has not been included in the databases. Based on the guidelines from the American College of Medical Genetics and Genomics, the variant was rated as pathogenic (PVS1+PS2+PM2_Supporting). Literature retrieval has identified 14 children with AKS and de novo mutations of the HNRNPK gene. Their clinical manifestations have included growth and motor retardation, various degree of mental retardation, facial dysmorphism and a high frequency of congenital heart malformations.

CONCLUSION

The AKS in this child may be attributed to the c478dupA frameshifting variant of the HNRNPK gene. Diagnosis of AKS should be suspected for children with mental retardation and multiple congenital malformation syndromes including Kabuki syndrome.