Hallermann-Streiff syndrome (HSS) is a form of ectodermal dysplasia, a group of syndromes deriving from abnormalities of the ectodermal structures (which include the hair, teeth, nails, sweat glands, eyes, face, and skull) that arise from the outer cell layer of a developing embryo. These are genetic disorders that may be inherited in an autosomal dominant or recessive manner.
HSS was first described in the medical literature in 1893. It was first reported by Hallermann in 1948 and by Streiff in 1950, when they observed patients with certain distinctive characteristics, including a birdlike face, in which the nose appears thin, sharp, and hooked; a prominent forehead; and an absent prominence of the chin when viewed from the side. Individuals with HSS may develop cataracts, a clouding that develops in the lens of the eye that may progress to vision loss if left untreated. Other characteristics of HSS include an underdeveloped jaw and dental defects, including the presence of natal teeth at birth and the absence or malformation of teeth; hypotrichosis (sparse hair); atrophy (degenerative skin changes), particularly in the scalp and nasal regions; short stature (i.e., dwarfism); and microphthalmia (unusually small eyes). HSS is a rare genetic disorder that is usually not inherited from, or passed down among, family members. HSS seems to occur randomly for unknown reasons, and may be the result of a mutation (a change to genetic material). Most cases of HSS are caused by a spontaneous genetic mutation or defect in the egg, sperm cells, or developing embryo. The pattern of inheritance in HSS is subject to some controversy. The genetic mutation that causes HSS has not yet been identified. It is possible that an elongation of one of the arms of the 10th chromosome may be a cause of HSS. This elongation was identified in one infant with symptoms of HSS. However, in other patients with symptoms of HSS, chromosomal analysis appeared normal. It has also been proposed that an increased rate in chromosomal breakage may explain the existence of some deoxyribonucleic acid (DNA) repair defects in HSS patients.
By 1981, about 150 cases of HSS had been reported in the available scientific literature. Since then, about 10 more cases have been reported. HSS appears to affect males and females in equal numbers. No race or ethnicity appears to be more affected than any other.
People with HSS are usually of normal intelligence and may have normal life expectancies. There is no cure for HSS, and treatment aims to reduce symptoms and prevent or treat complications.
Cataracts, ectodermal dysplasia, François dyscephaly syndrome, genetic mutation, Hallermann-Streiff-Francois syndrome, HSS, hypotrichosis, microphthalmia, obstructive sleep apnea, oculomandibulodyscephaly with hypotrichosis, oculomandibulofacial syndrome, sutural congenital alopecia.