Hallermann-Streiff Syndrome Health Article

Definition

Hallermann-Streiff syndrome is a rare genetic condition which causes characteristic facial features, visual abnormalities, tooth problems, short stature, and occasionally mental impairment.

Description

Hallermann-Streiff syndrome is also known as Francois dyscephaly syndrome, Hallermann-Streiff-Francois syndrome, oculomandibulodyscephaly with hypotrichosis, and oculomandibulofacial syndrome. The distinctive facial features of Hallermann-Streiff syndrome include a very small head that is unusually wide with a prominent forehead, a small underdeveloped jaw, an unusually small mouth, and/or a characteristic beak-shaped nose. Small eyes, clouding of the lens of the eyes (cataracts) and other eye problems often leading to blindness are common. Problems with the teeth, skin, hair, and short stature are also common. Most individuals are of normal intelligence but mental impairment has been reported in some. Most cases of Hallermann-Streiff syndrome occur randomly for unknown reasons and may be the result of mutations, or changes to the genetic material.

Genetic profile

Hallermann-Streiff syndrome is a genetic condition. Genes are units of hereditary material which are passed to a child by his or her parents. The information contained in genes is responsible for the growth and development of all the cells and tissues of the body. Most genes occur in pairs: one copy of each pair is inherited from the mother through the egg cell and one copy of each pair is inherited from the father through the sperm cell. If there is a gene alteration (mutation), this may interfere with normal growth and development. The specific gene responsible for Hallermann-Streiff syndrome has not yet been identified.

Most cases of Hallermann-Streiff syndrome occur randomly in families with no other affected individuals. In this situation, the gene alteration is a spontaneous mutation. This means that some unknown event has caused the gene (which functions normally in the parent) to change in either the father's sperm or the mother's egg from which the affected individual was conceived. A person who has Hallermann-Streiff syndrome due to a spontaneous mutation can pass on this mutated gene to offspring who will also be affected. The chance for someone with Hallermann-Streiff syndrome to have a child with the same condition is 50% in each pregnancy. There is also a 50% chance to have a child who is not affected with Hallermann-Streiff syndrome.

There are some reports in the literature which indicate that Hallermann-Streiff syndrome is inherited as a recessive condition. Recessive conditions occur when both copies of a gene pair are changed. The affected individual inherits one mutated gene from each parent. The parents of the affected individual are carriers for one changed copy of the gene pair but are not affected themselves. Carrier couples have a 25% chance in each pregnancy to have a child affected with the condition. Diagnosed individuals are at risk to have an affected child only if their partner is also affected or is a carrier. There is no clear agreement on whether Hallermann-Streiff syndrome can be inherited as a recessive condition. Some have argued that the families reported to have recessive Hallermann-Streiff syndrome in fact do not have this condition but some other condition with features very similar to Haller-mann-Streiff syndrome.

Demographics

Hallermann-Streiff syndrome affects both males and females in all ethnic groups. There have been over 150 cases reported in the literature.

Signs and symptoms

Hallermann-Streiff syndrome affects the face, skull, hair, skin, eyes, teeth, and overall growth and development.

Face and skull

The facial features of individuals with Hallermann-Streiff syndrome are distinctive. The face is small with a thin, tapering, pinched nose, and small chin. The head is small and unusually wide with a prominent forehead, a small underdeveloped jaw, and a small mouth. Characteristic changes in the bones of the skull and the long bones of the arms and legs can usually be seen on x ray. The hair is usually sparse, particularly that of the scalp, brows, and lashes. Often there is no hair around the front and sides of the head. The skin of the scalp is thin and taut, and scalp veins are prominent.

Potential complications in Hallermann-Streiff syndrome are related to the narrow upper airway associated with the shape of the skull, particularly the small chin, mouth, and nose. The narrow air passages may result in feeding difficulties and mild aspiration of food. This can lead to severe complications including early lung infection and breathing difficulties. The lung infection can be life-threatening. Some individuals may experience a temporary stop in breathing during sleep because of an obstruction caused by the shape of the skull (obstructive sleep apnea). Individuals with Hallermann-Streiff syndrome are also at increased risk of breathing difficulties when given a general anesthetic before surgery.