Naegeli syndrome, NFJ syndrome
Naegeli-Franceschetti-Jadassohn (NFJ) syndrome is a rare ectodermal dysplasia that affects the skin, sweat glands, nails, and teeth. Several families with multiple affected members (males and females) from several generations have been reported so far. Prevalence is estimated at 1 in 3 million. The cardinal features are absence of dermatoglyphics (fingerprints), reticular cutaneous hyperpigmentation (starting at about the age of 2 years without a preceding inflammatory stage), hypohidrosis with diminished sweat gland function and discomfort provoked by heat, nail dystrophy, tooth enamel defects, and moderate hyperkeratosis of the palms and soles. Diffuse palmoplantar keratoderma may coexist with punctate keratoses that are sometimes accentuated in the creases or exhibit a linear pattern. Congenital misalignment of the great toenails was reported in some patients. NFJ is inherited as an autosomal dominant condition and is caused by mutations in the KRT14 gene (17q11.2-17q21) encoding keratin 14. The disease is allelic to dermatopathia pigmentosa reticularis (see this term). Diagnosis is based on the typical clinical features and can be confirmed by molecular analysis. Differential diagnoses include incontinentia pigmenti, dermatopathia pigmentosa reticularis, dyskeratosis congenita, pachyonychia congenita and Dowling-Degos disease (see these terms). Prenatal diagnosis has not been reported so far. Treatment is symptomatic. The dry skin has to be moisturized with emollients, and hyperthermia should be prevented by use of appropriate clothing and physical cooling with wet dressings or cool water during warm periods. Dental care is imperative to prevent caries and tooth loss. The reticulate pigmentation fades after puberty and sometimes disappears completely in old age. Hypohidrosis, the most problematic symptom for patients, remains constant. Teeth are always severely affected, leading to early total loss.