A case of KMT2C gene mutation induced Kleefstra syndrome 2
10.3760/cma.j.cn101070-20240611-00359
- VernacularTitle:KMT2C基因变异致Kleefstra综合征2型1例
- Author:
Zhiping YIN
1
;
Weixin SHI
;
Wenting ZHANG
Author Information
1. 南通大学附属常州儿童医院消化营养科，常州 213003
- Publication Type:Journal Article
- Keywords:
Genetic analysis;
Kleefstra syndrome 2;
KMT2C gene
- From:
Chinese Journal of Applied Clinical Pediatrics
2025;40(2):130-132
- CountryChina
- Language:Chinese
-
Abstract:
The clinical data of a pediatric patient with Kleefstra syndrome 2 (KLEFS2) diagnosed at the Department of Gastroenterology and Nutrition, Changzhou Children′s Hospital Affiliated to Nantong University in May 2024 were retrospectively analyzed.The patient was a 2-year-and-6-month-old male who had delayed language-motor development, feeding difficulties, left cryptorchidism, and atrial septal defect.He could not say " papa/mama" at the age of 2 years and 6 months, with poor response to his name, and mainly consumed semi-liquid and liquid foods.Physical examination showed his weight was 11 kg (-1.64 SD) and his height was 82 cm (-2.94 SD).He had thick eyebrows, low nasal bridge, abundant hair on the back and the simian line on the palms of both hands.Whole exome sequencing revealed that the patient had a heterozygous variant in the histone-lysine N-methyltransferase 2C ( KMT2C) gene [c.5742(exon36)_5743(exon36)dup/p.(S1915Ffs*25)(NM_170606)].It could be the pathogenic variation according to the American College of Medical Genetics and Genomics variant interpretation guidelines.Based on the patient′s clinical characteristics and molecular genetic testing results, KLEFS2 was diagnosed.Sanger sequencing showed that the patient′s father has a wild-type KMT2C gene, and his mother carries this mutation in the KMT2C gene, but she only exhibits delayed physical development and short stature.KLEFS2 is a rare autosomal dominant genetic disease, and there is heterogeneity in its genetic variation and clinical phenotype.A total of 19 cases of KLEFS2 have been reported globally.This article reports new clinical manifestations of KLEFS2, including simian line and excessive hair growth.c.5742(exon36)_5743(exon36)dup is a newly found KMT2C mutation that enriches the KMT2C variation spectrum and expands the phenotypic spectrum of KLEFS2.
