Zhao X, Yu T, Tang J, Yao RE, Li N, Wang J. Two patients with KDM3B variants and new presentations of Diets-Jongmans syndrome.
Neurogenetics 2023;
24:95-101. [PMID:
36757469 DOI:
10.1007/s10048-023-00711-1]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 01/07/2023] [Indexed: 02/10/2023]
Abstract
KDM3B is located on chromosome 5q31 and encodes KDM3B, which is involved in histone demethylation and epigenetic regulation. Pathogenic KDM3B variants cause a dominantly inherited disorder presenting with intellectual disability (ID), short stature, and facial dysmorphism, named Diets-Jongmans syndrome. We describe two patients with KDM3B variants presenting with Diets-Jongmans syndrome. Genetic testing was performed because of the clinical data and a lack of a clear diagnosis in both patients. Candidate variants were verified by Sanger sequencing. After KDM3B variants were detected, in silico tools were used to predict the pathogenicity of the missense variants. A minigene assay was performed to evaluate the splicing effects of the c.5070 + 1G > A variant on KDM3B. Patient 1 mainly presented with repetitive upper respiratory tract infection and patient 2 presented with palpitation, shortness of breath, and pitting edema; both had ID. Whole exome sequencing identified variants of KDM3B. Patient 1 had the de novo KDM3B c.5070 + 1G > A variant, whereas patient 2 had the c.2828G > A (p.R943Q) variant. Transcriptional experiments of the splicing variant c.5070 + 1G > A revealed aberrant transcripts leading to truncated protein products. We found two pathogenic variants in KDM3B, one of which is novel. Both patients had additional clinical presentations, and patient 1 had transient neutropenia. KDM3B c.5070 + 1G > A is the first KDM3B splice-site variant and was identified as a germline variant. Neutropenia and cardiomyopathy are newly found presentations of Diets-Jongmans syndrome. Our report enriches our knowledge of the genotypic spectrum of the KDM3B variants and phenotypic diversity of Diets-Jongmans syndrome.
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