Böök syndrome

Böök syndrome, also known as PHC syndrome (premolar aplasia, hyperhidrosis, and canities prematura), is an extremely rare genetic disorder first described by Jan Arvid Böök in 1950 in a Swedish family. The condition is characterized by a triad of clinical features: premolar aplasia (congenital absence of premolar teeth), hyperhidrosis (excessive sweating, particularly of the hands and feet), and canities prematura (premature graying of the hair, often beginning in childhood or early adolescence). The syndrome primarily affects the ectodermal structures of the body, including the teeth, hair, and sweat glands. The dental manifestations involve the congenital absence of permanent premolar teeth, which can affect dental alignment and function. Hyperhidrosis can be socially distressing and may affect the palms, soles, and other body areas. Premature graying of the hair typically becomes apparent during childhood or adolescence. Some affected individuals may also have additional features such as a narrow palate. The syndrome follows an autosomal dominant inheritance pattern with variable expressivity, meaning that not all affected individuals within a family will display all three features to the same degree. There is no specific cure for Böök syndrome. Treatment is symptomatic and supportive. Dental management, including prosthetic replacement of missing teeth and orthodontic treatment, addresses the premolar aplasia. Hyperhidrosis may be managed with topical antiperspirants, iontophoresis, or in severe cases, botulinum toxin injections. Premature graying is a cosmetic concern that can be addressed with hair dye if desired. Genetic counseling is recommended for affected families.

Common questions about Böök syndrome