Immune system disturbances in Clouston syndrome

Multidisciplinary interventions in ectodermal dysplasia: A clinical case report

Ectodermal dysplasia (ED) is a spectrum of inherited disorders that compromise the development and function of ectodermal structures, like hair, nails, and teeth. This case report describes a 17-year-old male with sparse hair and cognitive difficulties who was diagnosed with ED in childhood. A multidisciplinary evaluation with dermatology, neurology, and dentistry revealed characteristic clinical features, and the histopathological diagnosis was confirmed via punch biopsy. Also, ED poses challenges beyond dermatologic manifestations, affecting cognitive function, psychological well-being, and nutrition. Multidisciplinary management, early diagnosis, and awareness are crucial for optimizing patient outcomes and exploring potential therapies.

Hidrotic ectodermal dysplasia in a Chinese pedigree: A case report

BACKGROUND

We report on a large family of Chinese Han individuals with hidrotic ectodermal dysplasia (HED) with a variation in GJB6 (c.31G>A). The patients in the family had a triad of clinical manifestations of varying degrees. Although the same variation locus have been reported, the clinical manifestations of this family were difficult to distinguish from those of congenital thick nail disorder, palmoplantar keratosis, and congenital hypotrichosis.

CASE SUMMARY

This investigation involved a large Chinese family of 46 members across five generations and included 12 patients with HED. The proband (IV4) was a male patient with normal sweat gland function and dental development, no skeletal dysplasia, no cognitive disability, and no hearing impairments. His parents were not consanguineously married. Physical examination of the proband revealed thinning hair and thickened grayish-yellow nails and toenails with some longitudinal ridges, in addition to mild bilateral palmoplantar hyperkeratosis. GJB6, GJB2, and GJA1 have been reported to be the causative genes of HED; therefore, we subjected the patient’s samples to Sanger sequencing of these three genes. In this family, the variation locus was at GJB6 (c.31G>A, p.Gly11Arg). Overexpression vectors of wild-type GJB6 and its variants were established and transfected into HaCaT cell models, and the related mRNA and protein expression changes were determined using real-time reverse transcriptase-polymerase chain reaction and Western blot, respectively.

CONCLUSION

We report another HED phenotype associated with GJB6 variations, which can help clinicians to diagnose HED despite its varying presentations.

Magnesium transporter 1 (MAGT1) deficiency causes selective defects in N-linked glycosylation and expression of immune-response genes

Magnesium transporter 1 (MAGT1) critically mediates magnesium homeostasis in eukaryotes and is highly-conserved across different evolutionary branches. In humans, loss-of-function mutations in the MAGT1 gene cause X-linked magnesium deficiency with Epstein-Barr virus (EBV) infection and neoplasia (XMEN), a disease that has a broad range of clinical and immunological consequences. We have previously shown that EBV susceptibility in XMEN is associated with defective expression of the antiviral natural-killer group 2 member D (NKG2D) protein and abnormal Mg²⁺ transport. New evidence suggests that MAGT1 is the human homolog of the yeast OST3/OST6 proteins that form an integral part of the N-linked glycosylation complex, although the exact contributions of these perturbations in the glycosylation pathway to disease pathogenesis are still unknown. Using MS-based glycoproteomics, along with CRISPR/Cas9-KO cell lines, natural killer cell-killing assays, and RNA-Seq experiments, we now demonstrate that humans lacking functional MAGT1 have a selective deficiency in both immune and nonimmune glycoproteins, and we identified several critical glycosylation defects in important immune-response proteins and in the expression of genes involved in immunity, particularly CD28. We show that MAGT1 function is partly interchangeable with that of the paralog protein tumor-suppressor candidate 3 (TUSC3) but that each protein has a different tissue distribution in humans. We observed that MAGT1-dependent glycosylation is sensitive to Mg²⁺ levels and that reduced Mg²⁺ impairs immune-cell function via the loss of specific glycoproteins. Our findings reveal that defects in protein glycosylation and gene expression underlie immune defects in an inherited disease due to MAGT1 deficiency.