Abstract:

Objective To investigate the clinical characteristics and the gene mutation site of a family with Wiedemann-Steiner syndrome（WDSTS） caused by a new mutation in KMT2A gene. Methods The clinical data and peripheral blood samples of the proband and family members were collected. Genomic DNA was extracted，and whole-exome sequencing，datum analysis and Sanger sequencing verification were performed. Results The clinical characteristics of the proband included intellectual disability，special facial features，growth and development retardation and multiple hair on the limbs. The proband，his mother and his younger brother all carried a heterozygous frameshift mutation in the KMT2A gene at 11q23.3（NM_005933.4）：c.3061_3062delAA/p.Lys1021fs*17，and it was a new mutation in the KMT2A gene. After Sanger sequencing verification，it was determined that KMT2A gene c.3061_3062delAA/p.Lys1021fs*17 was pathogenic. Conclusions A new mutation site in the KMT2A gene c.3061_3062delAA/p.Lys1021fs*17 has been found，expanding the pathogenic gene and phenotypic spectrum of WDSTS.

Key words: KMT2A gene, Genetic mutation, Wiedemann-Steiner syndrome