Marie-Unna Hereditary Hypotrichosis

The document reports a case of Marie-Unna hereditary hypotrichosis (MUHH), a rare autosomal dominant disorder characterized by a distinctive pattern of hair loss that varies with the child's age. The case involves a 12-year-old male child of Dravidian origin who presented with progressive thinning of hair over two years. He was born with sparse hair, which regrew coarsely and curly, but then began to fall out again. The child's clinical features, including sparse hair on the scalp, eyebrows, and eyelashes, and the absence of systemic involvement, led to the diagnosis of MUHH. Light microscopy of the hair shaft showed dark pigmentation and irregular twisting. Genetic testing was not performed due to its unavailability. MUHH is characterized by sparse or absent hair at birth, regrowth of coarse hair in childhood, and progressive hair loss approaching puberty. The condition is linked to mutations in the U2HR gene on chromosome 8p21, with 17 mutations identified in various ethnic backgrounds. There is no effective treatment, and the diagnosis is based on the pattern of hair loss and hair shaft abnormalities.