Hypotrichosis with juvenile macular degeneration

Hypotrichosis with juvenile macular degeneration (HJMD), also known as hypotrichosis with juvenile macular dystrophy, is a rare autosomal recessive disorder characterized by the combination of sparse hair (hypotrichosis) present from early childhood and progressive degeneration of the macula of the eye beginning in the first or second decade of life. The condition is caused by mutations in the CDH3 gene, which encodes P-cadherin, a calcium-dependent cell adhesion protein expressed in the retinal pigment epithelium and hair follicles. Affected individuals typically present with sparse, short scalp hair from birth or early infancy. The hair is often fine, fragile, and slow-growing, and may also affect eyebrows, eyelashes, and body hair. The macular dystrophy usually becomes apparent during childhood or adolescence, with progressive loss of central vision that can lead to legal blindness by early adulthood. Retinal findings include macular atrophy, pigmentary changes, and loss of the foveal reflex. Peripheral vision is generally preserved. There is currently no cure or specific treatment for HJMD. Management is supportive and includes regular ophthalmologic monitoring, low-vision aids, and adaptive strategies for visual impairment. Genetic counseling is recommended for affected families. The condition does not typically affect other organ systems or life expectancy. Early diagnosis through genetic testing of the CDH3 gene can help families prepare for the progressive visual decline and access appropriate support services.

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