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A rare form of ectodermal dysplasia with premolar aplasia, hyperhidrosis, premature cavities, and premature whitening of the hair.

Premolar Aplasia, Hyperhidrosis, and Premature Cavities Syndrome; PHC Syndrome.

Extremely rare.

Autosomal dominant with high penetrance.

Unknown, but PHC syndrome belongs to the heterogeneous group of ectodermal dysplasias that includes more than 150 diseases with various inheritance modes and genetic heterogenicity. In ectodermal dysplasia, the initial factor seems to be a perturbation of epithelial morphogenesis.

Premature whitening of the hair with characteristic dental defects and a family with similar history.

Dental affection is the most frequent sign. Anodontia or oligodontia can affect all teeth, but missing premolars are the most characteristic. Abnormal dental position and tooth shape anomaly may be observed. Premature whitening of hair can appear even in childhood and may be associated with poorly formed dermatoglyphs and distal digital creases. Increased sweating of the hands and feet are very frequent (hyperhidrosis).

No other disorders are associated with this particular syndrome. However, because of a mild depression of the immune system and a defect in the respiratory mucous glands, other forms of ectodermal dysplasia often show a predisposition to respiratory tract infections, which are potentially life-threatening. No such reports exist specifically for this syndrome, but nevertheless should be kept in mind when assessing the patient. Evaluate dental position, aspect, and mobility, and severity of hyperhidrosis.

No reports of anesthetic experience with these patients are available. Patients may present for surgical management of hyperhidrosis. Extremity lesions can interfere with pulse oximetry. Direct laryngoscopy must be done very carefully considering the dental anomalies.

Hyperhidrosis must be evaluated before use of parasympatholytic drugs (flush, hyperthermia more frequent with atropine).

Far more than 100 different forms of ectodermal dysplasia are known; only a few are mentioned here to show the wide variety of this entity.

Rapp-Hodgkin Hypohidrotic Ectodermal Dysplasias: Autosomal dominant inherited anhidrotic ectodermal dysplasia with cleft lip/palate, hypodontia, hair anomalies and alopecia in adulthood, and nail anomalies.

Christ-Siemens-Touraine Syndrome: Inherited disease characterized by absence of sweat glands (anhidrosis, distorted heat regulation), and sebaceous glands (xerosis), hypotrichosis, poor dental development, and facial abnormalities (prominent forehead, thick lips, saddle nose).

Psaume Syndrome (Orofaciodigital Syndrome Type I): A syndrome with X-linked dominant transmission or sporadic (75%) occurrence with oral (tongue and dental anomalies, cleft lip/palate), facial (hypertelorism, telecanthus, micrognathia), digital (brachydactyly, syndactyly, duplication of hallux), cerebral (cerebellar atrophy, agenesis of the corpus callosum, Dandy-Walker malformation, mild mental retardation), and renal anomalies (polycystic kidney disease). Almost all affected patients are females, although some affected males have been reported.

Ellis-van Creveld Syndrome: Autosomal recessive inherited syndrome with congenital cardiac defects, pulmonary hypoplasia because of a small chest, dwarfism, polydactyly, nail dystrophy, and dystonias.

Clouston Syndrome (...

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