Marie Unna hereditary hypotrichosis: A Turkish family with loss of eyebrows and a U2HR mutation

Genetic Hair Disorders: A Review

Hair loss in early childhood represents a broad differential diagnosis which can be a diagnostic and therapeutic challenge for a physician. It is important to consider the diagnosis of a genetic hair disorder. Genetic hair disorders are a large group of inherited disorders, many of which are rare. Genetic hair abnormalities in children can be an isolated phenomenon or part of genetic syndromes. Hair changes may be a significant finding or even the initial presentation of a syndrome giving a clue to the diagnosis, such as Netherton syndrome and trichothiodystrophy. Detailed history including family history and physical examination of hair and other ectodermal structures such as nails, sweat glands, and sebaceous glands with the use of dermoscopic devices and biopsy all provide important clues to establish the correct diagnosis. Understanding the pathophysiology of genetic hair defects will allow for better comprehension of their treatment and prognosis. For example, in patients with an isolated hair defect, the main problem is aesthetic. In contrast, when the hair defect is associated with a syndrome, the prognosis will depend mainly on the associated condition. Treatment of many genetic hair disorders is focused on treating the primary cause and minimizing trauma to the hair.

Marie-unna hereditary hypotrichosis

Marie-Unna type of hereditary hypotrichosis is a rare autosomal dominant disorder that has a distinctive type of hair loss pattern that varies with child's age. It is characterized by sparse or absent hair at birth with regrowth of coarse, wiry twisted hair from childhood, followed by progressive loss on approaching puberty. We report a 12-year-old male child with characteristic clinical features suggestive of hereditary hypotrichosis of Marie-Unna type.

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.