Hallermann-Streiff syndrome

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Hallermann-Streiff syndrome

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 beakshaped 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 Hallermann-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.

Eyes

Individuals with Hallermann-Streiff syndrome may be born with clouding of the lenses of the eyes (congenital cataracts). Congenital cataracts are the most common eye disorder and are usually the reason for a visit to the eye specialist in early life. The cataracts have been reported to spontaneously disappear in some cases. The second most common eye problem is that the eyes are unusually small. Other eye problems may include rapid, involuntary eye movements, crossing of the eyes, and/or decreased visual clarity, and in some cases, blindness.

Teeth

Dental problems are very common. They may include the presence of teeth at birth and the presence of extra teeth. Underdevelopment of tooth enamel and cavities are also common. As well, there may be absence, malformation, and/or improper alignment of certain teeth.

Growth and development

Most individuals with Hallermann-Streiff syndrome are born at term but about one-third are born premature and/or have a low birth weight. Short stature is seen in about half of the individuals with Hallermann-Streiff syndrome. The average final height for females is about 60 in (152 cm) and for males it is about 61 in (155 cm).

Most individuals are of normal intelligence; however, it is estimated that 15-30% of individuals with Hallermann-Streiff syndrome show some degree of mental impairment or slow development. Hyperactivity and seizures have been reported in a small number of individuals.

Other

A small number of individuals with Hallermann-Streiff syndrome have heart defects (such as a hole in the heart). There has also been a report of an individual with a weakened immune system.

Diagnosis

The diagnosis of Hallermann-Streiff syndrome is based on the presence of certain features including the characteristic facial, eye, dental, hair, and skin findings. The main features indicative of Hallermann-Streiff syndrome include a small, wide head with a prominent forehead, the characteristic small jaw and mouth with a pinched nose, cataracts, small eyes, dental abnormalities, sparse or absent hair, thin skin, and short stature. X rays of the bones of the body may be helpful in establishing a diagnosis of Hallermann-Streiff syndrome because there are characteristic changes evident in the bones of individuals with this condition. There is no laboratory test which can be done to confirm the diagnosis. Genetic testing to identify the specific genetic alteration causing the condition is not available since the gene for Hallermann-Streiff syndrome has not been identified. Testing for Hallermann-Streiff syndrome in an unborn baby has not been done. It may be possible to detect the abnormal head shape and small chin on ultrasound (sound wave picture) of the developing baby but this has not been documented in the literature.

Treatment and management

There is no cure for Hallermann-Streiff syndrome. In general, an individual with Hallermann-Streiff syndrome requires a team of specialized doctors for treating the various problems which can occur. Assessments by a dentist, dental surgeon, and oral-facial surgeon may also be necessary to evaluate the teeth and difficulties caused by the small chin and mouth. An assessment for possible airway problems is essential. Any individual with Hallermann-Streiff syndrome who shows signs of day time sleepiness or snoring should be referred to a sleep center for proper diagnosis and treatment of possible obstructive sleep apnea. Treatment for this condition may include surgical procedures such as making a hole in the trachea through the neck to relieve whatever is obstructing the breathing (tracheotomy). Other surgical treatments may include advancing the chin, reducing the size of the tongue, and/or removing the tonsils. Non-surgical treatments may include medications, providing the individual with an oxygen mask, and modifying his or her sleeping position.

An individual with Hallermann-Streiff syndrome should be examined by an eye specialist (ophthalmologist) for signs and symptoms of eye problems. Surgery for some types of eye problems (cataracts, crossed eyes) may be necessary. Individuals who are blind or at risk to lose their eyesight may benefit from being referred to an association for the blind for guidance and counseling.

An examination by a heart specialist (cardiologist) for possible heart problems and by an immune specialist (immunologist) for possible decreased immune function is also recommended. Some types of heart problems may be treated with medications or may require surgical correction.

For individuals with developmental delay or mental impairment, treatment may include special education, speech therapy, occupational therapy, and physical therapy. Drugs may be used to treat hyperactivity, seizures, and other problems.

Some individuals with Hallermann-Streiff syndrome may seek cosmetic surgery for the various effects the syndrome has on the face and skull. Counseling by psychologists may also help individuals with Hallermann-Streiff syndrome cope with the psychological impact of having a facial difference.

Individuals with Hallermann-Streiff syndrome and their families may also benefit from genetic counseling for information on the condition and recurrence risks for future pregnancies.

Prognosis

Individuals diagnosed with Hallermann-Streiff syndrome typically have normal intelligence and life-spans when complications of this disorder are properly managed. A major difficulty for individuals with Hallermann-Streiff syndrome is that the visual problems can often lead to blindness, despite surgery. Lung infections can be life-threatening to these patients and must be treated immediately. Breathing problems are another serious complication resulting from the abnormal skull formation that narrows the upper airway. Although uncommon, developmental delay and mental impairment have been reported in a minority of individuals affected with Hallermann-Streiff syndrome. These individuals with significant mental impairment may require life-long supervision.

Resources

PERIODICALS

Cohen, M. M. "Hallermann-Streiff Syndrome: A Review." American Journal of Medical Genetics 41 (1991): 488-499.

David, L. R., et al. "Hallermann-Streiff Syndrome: Experience with 15 Patients and Review of the Literature." Journal of Craniofacial Surgery 2 (March 1999): 160-8.

ORGANIZATIONS

FACES: The National Craniofacial Association. PO Box 11082, Chattanooga, TN 37401. (423) 266-1632 or (800) 332-2373. [email protected]. <http://www.faces-cranio.org/>.

National Eye Institute. 31 Center Dr., Bldg. 31, Room 6A32, MSC 2510, Bethesda, MD 20892-2510. <http://www.nei.nih.gov>.

National Organization for Rare Disorders (NORD). PO Box 8923, New Fairfield, CT 06812-8923. (203) 746-6518 or (800) 999-6673. Fax: (203) 746-6481. <http://www.rarediseases.org>.