Background
We report the first case of a family with co‐occurrence of Wilson disease (WD), an autosomal recessive disorder of copper metabolism, and X‐linked agammaglobulinemia (XLA), a primary immunodeficiency disorder (PIDD) that features marked reduction in circulating B lymphocytes and serum immunoglobulins.
Methods and Results
Through utilization of a multiplexed biomarker peptide quantification method known as the immuno‐SRM assay, we were able to simultaneously and independently identify which family members are affected with WD and which are affected with XLA using dried blood spots (DBS).
Conclusion
Being able to delineate multiple diagnoses using proteolytic analysis from a single DBS provides support for implementation of this methodology for clinical diagnostic use as well as large‐scale population screening, such as newborn screening (NBS). This could allow for early identification and treatment of affected individuals with WD or XLA, which have been shown to reduce morbidity and decrease mortality in these two populations.
Glycosylation is a critical post/peri‐translational modification required for the appropriate development and function of the immune system. As an example, abnormalities in glycosylation can cause antibody deficiency and reduced lymphocyte signaling, although the phenotype can be complex given the diverse roles of glycosylation. Human MGAT2 encodes N‐acetylglucosaminyltransferase II, which is a critical enzyme in the processing of oligomannose to complex N‐glycans. Complex N‐glycans are essential for immune system functionality, but only one individual with MGAT2‐CDG has been described to have an abnormal immunologic evaluation. MGAT2‐CDG (CDG‐IIa) is a congenital disorder of glycosylation (CDG) associated with profound global developmental disability, hypotonia, early onset epilepsy, and other multisystem manifestations. Here, we report a 4‐year old female with MGAT2‐CDG due to a novel homozygous pathogenic variant in MGAT2, a 4‐base pair deletion, c.1006_1009delGACA. In addition to clinical features previously described in MGAT2‐CDG, she experienced episodic asystole, persistent hypogammaglobulinemia, and defective ex vivo mitogen and antigen proliferative responses, but intact specific vaccine antibody titers. Her infection history has been mild despite the testing abnormalities. We compare this patient to the 15 previously reported patients in the literature, thus expanding both the genotypic and phenotypic spectrum for MGAT2‐CDG.
ATP6AP1-CDG is an X-linked disorder typically characterized by hepatopathy, immunodeficiency, and an abnormal type II transferrin glycosylation pattern. Here, we present 11 new patients and clinical updates with biochemi-
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