This salt-retaining, water-losing phenotype of HHS subjects links to the last findings of our study: despite the lack of association with many clinical characteristics, the amount of TEWL measured at rest correlates with sweat volume and with surrogates of the skin microvascular status, i.e., circulating VEGF-c and Hb in the skin. The gene discussed is GSTM1; the disease is hypotrichosis 1.