TFAP2A gene and inherited as an autosomal dominant trait.

The characteristic signs and symptoms of BOFS include skin defects, eye abnormalities, and distinctive facial features. These features vary among affected individuals. The skin defects include proliferation of blood vessels (hemangiomatous) in the lower neck or upper chest; lumps in the area of the neck or collarbone (branchial cleft sinuses); and linear skin lesions behind the ears. Eye abnormalities can include microphthalmia, coloboma, and strabismus. The distinctive facial features can include widely spaced eyes; the presence of a pseudocleft of the upper lip resembling a poorly repaired cleft lip; a malformed nose with a broad bridge and flattened tip; blockage of the tear ducts (lacrimal duct obstruction); and malformed ears. Often, affected individuals may have burn-like lesions behind the ears. Other features can include delayed growth, thymic and kidney abnormalities, dental abnormalities, and hearing loss. Intellect is usually normal.

TFAP2Agene in each cell is sufficient to cause this condition.