1. Deficiency of the human cysteine protease inhibitor cystatin M/E causes hypotrichosis and dry skin.
- Author
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van den Bogaard EHJ, van Geel M, van Vlijmen-Willems IMJJ, Jansen PAM, Peppelman M, van Erp PEJ, Atalay S, Venselaar H, Simon MEH, Joosten M, Schalkwijk J, and Zeeuwen PLJM
- Subjects
- Alopecia genetics, Child, Consanguinity, Female, Humans, Loss of Function Mutation, Male, Exome Sequencing, Alopecia congenital, Cystatin M deficiency, Cystatin M genetics, Cysteine Proteinase Inhibitors metabolism, Skin Diseases genetics
- Abstract
Purpose: We aimed to assess the biological and clinical significance of the human cysteine protease inhibitor cystatin M/E, encoded by the CTS6 gene, in diseases of human hair and skin., Methods: Exome and Sanger sequencing was performed to reveal the genetic cause in two related patients with hypotrichosis. Immunohistochemical, biophysical, and biochemical measurements were performed on patient skin and 3D-reconstructed skin from patient-derived keratinocytes., Results: We identified a homozygous variant c.361C>T (p.Gln121*), resulting in a premature stop codon in exon 2 of CST6 associated with hypotrichosis, eczema, blepharitis, photophobia and impaired sweating. Enzyme assays using recombinant mutant cystatin M/E protein, generated by site-directed mutagenesis, revealed that this p.Gln121* variant was unable to inhibit any of its three target proteases (legumain and cathepsins L and V). Three-dimensional protein structure prediction confirmed the disturbance of the protease/inhibitor binding sites of legumain and cathepsins L and V in the p.Gln121* variant., Conclusion: The herein characterized autosomal recessive hypotrichosis syndrome indicates an important role of human cystatin M/E in epidermal homeostasis and hair follicle morphogenesis.
- Published
- 2019
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