Abstract:

Objective To report the clinical and genetic characteristics of three cases of Wiedemann-Steiner syndrome (WDSTS) caused by KMT2A gene mutation, and improve the understanding of the disease and the efficiency of diagnosis and treatment. Methods The clinical data of three cases of WDSTS caused by KMT2A gene mutation in three families diagnosed in Shengjing Hospital of China Medical University from December 2019 to September 2021 were reviewed, and the clinical and genetic characteristics of WDSTS patients reported in the literature were reviewed and summarized. Results All three cases were diagnosed in infancy, with the youngest age of diagnosis of two months old, and the reasons for consultation were growth retardation and anorexia, respectively. Similar to those in previous literature, the clinical manifestations were special facial features, malnutrition (3/3), feeding difficulties, sleep disorders, hirsutism (2/3), and developmental delay (1/3). The clinical manifestations that had not been reported before were umbilical hernia and inguinal hernia. All three cases were de novo frameshift variants, which occurred in exon 3 and 27 in hot spot variants region and exon 11 in non-hot spot variants region, respectively. Conclusions Wiedemann-Steiner syndrome should be considered in children with malnutrition, feeding difficulty and developmental delay, combined with special facial features and specific hirsute. High-throughput exome sequencing should be used to facilitate early diagnosis. De novo frameshift variants of KMT2A gene are common, with hot spots in exon 27 and 3. The three unreported frameshift variants in this study enrich the mutation spectrum of this gene. In addition, patients with variants in the CXXC region of the KMT2A gene may have a more severe clinical phenotype.

Key words: malnutrition, feeding difficulty, Wiedemann-Steiner syndrome