Hyper-IgM and acquired C1q complement deficiency in a patient with de novo  ATM mutation. Issue 2 (27th February 2023)

• Record Type: Journal Article
• Authors: Lee, Adrian Y S; Dai, Pei; Burnett, Leslie; Wei, Xiumei; Kakar, Fakhria; Ohnesorg, Thomas; Lin, Ming-Wei
• Is Part Of: Oxford medical case reports. Volume 2023:Issue 2(2023)
• Publication Date: 2023-02-27
• Subjects: Clinical medicine -- Case studies -- Periodicals; 616.09
• DOI: 10.1093/omcr/omad005
• Languages: English
• ISSNs: 2053-8855

Abstract

ABSTRACT: Hyper-IgM syndrome (HIGM) is a rare immunodeficiency phenotype that is usually accompanied by serious infections. We present a curious case of the incidental detection of HIGM in a 45-year-old male with complement C1q deficiency. He had relatively mild sinopulmonary infections, recurrent skin infections and lipomas in his adulthood. Investigations revealed normal enumeration of total peripheral blood B cells and reduced expression of CD40L on his CD4 + T cells. C1q was noted to be absent, due to a peripheral inhibitor such as an autoantibody. Genomic sequencing of the patient and his parents revealed a novel, de novo heterozygous mutation in the ATM (ataxia telangiectasia mutated) gene although he displayed no clinical evidence of ataxia telangiectasia. This is a rare case of HIGM and acquired C1q deficiency. We present full phenotyping data that contributes to the growing understanding to these interesting immunodeficiencies.