Marie Unna hereditary hypotrichosis: Identification of a U2HR mutation in the family from the original 1925 report

An immune regulatory CCT repeat containing oligodeoxynucleotide capable of causing hair loss in male mice

An oligodeoxynucleotide with CCT repeats (CCT ODN) has been found in our previous study to selectively downregulate Toll-like receptor 7/9 (TLR7/9)-mediated immune responses both in vitro and in vivo. In this study, we unexpectedly found that CCT ODN induced severe patchy hair loss around the mouth in male F1 mice (female Balb/c × male C57BL/6) with lupus-like nephritis induced by injecting allogenic lymphocytes and also in male Balb/c mice, but not in female F1 mice and Balb/c mice and either gender of C57BL/6 mice. Increased infiltration of natural killer group 2, member D (NKG2D⁺) cells in hair loss skin and upregulated interferon-gamma (IFN-γ) messenger RNA expression in cultured splenocytes were observed in male Balb/c mice. The CCT ODN-conditioned supernatants of cultured mouse splenocytes caused catagen-like changes to hair follicles (HFs). We hypothesized that the CCT ODN could induce patchy hair loss in the male mice with certain genetic traits by mobilizing NKG2D⁺ cells to HFs and by inducing the production of IFN-γ from immune cells. Taken together these data indicated that a gender and genetic preference of immune-regulatory oligonucleotides is causing unexpected clinical situations such as hair loss.

Identification of a novel U2HR mutation in a Korean woman with Marie Unna hereditary hypotrichosis

Marie Unna hereditary hypotrichosis (MUHH) is a rare autosomal dominant genodermatosis characterized by progressive non-scarring hair loss. Mutation of the U2HR gene, located in chromosome 8p21, is generally responsible for MUHH development. Until now, 17 mutations of U2HR have been identified from various ethnic backgrounds, but U2HR mutations have been identified mostly in Chinese families and only one Japanese patient with MUHH among Asian populations. Here, we report the first Korean case of MUHH with a novel heterozygous missense mutation (c.80C>T) in U2HR that has not been documented to date. Genetic analysis further revealed that this mutation is responsible for the hair morphology phenotype presented in this case. This finding contributes to expansion of the mutant spectrum of U2HR, supporting the possibility of racial differences in terms of genetic mutations of MUHH.

Nucleic acid-based non-invasive prenatal diagnosis of genetic skin diseases: are we ready?

The discovery of circulating fetal nucleic acids is a great step on the way of developing non-invasive prenatal diagnosis (NIPD) for genetic disorders. Here, we briefly discuss the current applications of circulating fetal nucleic acids in genetic testing for different kinds of hereditary diseases with an emphasis on using circulating cell-free fetal DNA in diagnosis of monogenic disorders. As the genetic skin disorders impair the quality of life at different levels, we next discuss some ethical issues in NIPD for genetic skin diseases of various severities and in particular, the responsibility of doctors and parents, respectively, in the prenatal genetic testing.

Do you know this syndrome?

Congenital hypotrichosis and Stargardt macular dystrophy are rare autosomal recessive disorder of unknown etiology respectively characterized by hair loss, macular degeneration and severe progressive vision reduction. There are few reports in the literature with this association. Studies show that the defective gene is on the chromosome I6q22.1 and involve cadherin molecule in the pathogenesis. Early recognition of these disorders often starts with hair changes and should alert the dermatologist for an eye examination thereby avoiding more severe ocular defect.