Basan syndrome (also known as Basan-Baird syndrome) is a very rare ectodermal dysplasia that was first described in 1964. Since then, there have been fewer than 10 total kindreds described with the condition. It is an autosomal dominant disorder with high penetrance and variable expressivity. In some affected families, presence of the syndrome was associated with mutations of the skin-specific isoform of the SMARCAD1 gene at chromosome 4q22.3. The function of this gene remains unknown.

Affected individuals universally have adermatoglyphia, or absence of dermal ridges on the palms and soles. This typically involves the entire volar surface, but incomplete adermatoglyphia, sparing the ulnar aspect of the fifth finger and palm, has been observed. The affected areas characteristically lack sweating. Some children develop a palmoplantar keratoderma with calluses on the hands and feet that progressively thicken as they get older. These are often associated with dryness and painful fissures that get worse with exposure to heat or cold.

Congenital facial milia, frequently extensive, are another near universal feature of the syndrome. These are usually transient and spontaneously resolve by 6 months of age. Another common feature is thin acral skin with vesicles and bullae that presents at birth or in early infancy. Erosions heal rapidly, disappearing within months without scarring. Recurrent acral blistering in childhood is atypical but has been observed.

Other variable features include syndactyly, clinodactyly, camptodactyly, tapered fingers, knuckle pads, hyperpigmented macules on the hands and feet, single transverse palmar crease, flexion contractures of digits, and nail dystrophy.