Dubowitz syndrome

Definition

Dubowitz syndrome is a genetic disorder defined by slow growth, a characteristic facial appearance, and a small head.

Description

Dubowitz syndrome was first described in 1965 by the English physician Dr. Victor Dubowitz. This genetic disorder causes growth retardation both before and after birth. It is primarily diagnosed through the distinctive facial features of affected individuals, including a small triangular-shaped face with a high forehead and wide-set, slitted eyes. A number of other symptoms, most commonly irritation and itching of the skin (eczema), may be present in infants born with Dubowitz syndrome.

Genetic profile

Dubowitz syndrome is passed on through an autosomal recessive pattern of inheritance . Autosomal means that the syndrome is not carried on a sex chromosome , while recessive means that both parents must carry the gene mutation in order for their child to have the disorder. Parents with one child affected by Dubowitz syndrome have a 25% chance that their next child will also be affected with the disease.

The specific gene mutation responsible for Dubowitz syndrome had not yet been identified.

Demographics

Cases of Dubowitz syndrome have been reported from many different regions of the world with the majority coming from the United States, Germany, and Russia. There does not appear to be any clear-cut ethnic pattern to the incidence of the syndrome. Dubowitz syndrome appears to affect males and females with equal probability. The overall incidence of the disorder has not been established since it is very rare. Only about 142 cases have been reported worldwide.

Signs and symptoms

Physical characteristics

The symptoms of people diagnosed with Dubowitz syndrome vary considerably. However, the most common physical characteristics associated with Dubowitz syndrome are growth retardation, characteristic facial appearance, and a very small head (microcephaly). A wide variety of secondary physical characteristics may be present.

GROWTH RETARDATION Children born with Dubowitz syndrome usually have a low birth weight. Slower than normal growth continues after birth. Even if the infant is born in the normal range, the height and weight gradually falls toward the low end of growth curves during childhood. However, Dubowitz syndrome is not a form of dwarfism, because affected individuals have normally proportioned bodies.

FACIAL APPEARANCE The characteristic facial appearance of people with Dubowitz syndrome is the primary way in which the disorder is recognized. The face is small and often triangular in shape with a pointed, receding chin. The nose is broad with a wide or rounded tip. The eyes are set far apart and sometimes appear slitted due to a decreased distance between top and bottom eyelids or a drooping top eyelid. The forehead is high, broad, and sloping. Eyebrows and hair are thin or absent. The ears may be abnormally shaped or placed.

MICROCEPHALY Infants born with Dubowitz syndrome have primary microcephaly, or a small head size at birth. By definition, in microcephaly the circumference of the head is in the second percentile or less, meaning that 98% or more of all infants have a larger head circumference than an infant with microcephaly.

OTHER PHYSICAL CHARACTERISTICS There are many other physical characteristics that have been observed in the majority of cases of Dubowitz syndrome, although they are not present in all affected individuals. These include:

• A soft or high-pitched cry or voice
• Partial webbing of the toes
• Cleft palate or less severe palate malformations
• Genital abnormalities, including undescended testicles
• Gastroesophophageal reflux
• Inflammation and itching of the skin (eczema)

Mental and behavioral characteristics

Despite the small head size of children born with Dubowitz syndrome, developmental delay is not observed in all cases. Estimates of the incidence of developmental delay in cases of Dubowitz syndrome range from 30% to 70%, and in most cases the level of the mental retardation is rather mild.

A number of behavioral characteristics have been described by parents of children with Dubowitz syndrome as well as in the medical literature. These include:

• Extreme hyperactivity
• Temper tantrums, difficulty in self-calming
• Preference for concrete thinking rather than abstract thinking
• Language difficulties
• Shyness and aversion to crowds
• Fondness for music and rhythm

Diagnosis

Since the genetic cause is not known, there is no specific medical test that can definitively assign the diagnosis of Dubowitz syndrome. The diagnosis is usually based on the characteristic facial appearance of the affected individual as well as on other factors such as growth data and medical history. The diagnosis is easily missed if the physician is not familiar with genetic pediatric conditions.

Treatment and management

A number of chronic medical conditions are associated with Dubowitz syndrome. These include:

• Inflammation and itching of the skin (eczema)
• Susceptibility to viral infections
• Allergies
• Chronic diarrhea or constipation
• Feeding difficulties and vomiting

These conditions need to be managed individually with appropriate treatments. For example, skin creams containing corticosteroid drugs are used to treat eczema.

Other physical problems caused by Dubowitz syndrome, such as drooping eyelids (ptosis) or cardiovascular defects, can be corrected through surgery.

Prognosis

The prognosis for individuals affected by Dubowitz syndrome is good provided that management of their medical conditions is maintained. Dubowitz syndrome has not been reported to cause shortened lifespan or any degenerative conditions. People with Dubowitz syndrome can expect to survive to adulthood and lead a fairly normal lifestyle, although most have some level of mental retardation.

Resources

PERIODICALS

Tsukahara, M., and J. Opitz. "Dubowitz Syndrome: Review of 141 Cases Including 36 Previously Unreported Patients." American Journal of Human Genetics (1996): 277-289.

ORGANIZATIONS

Dubowitz Syndrome Nationwide Support Group Network. RR 1 Box 114, Downs, IL 61736. (309) 724-8407.

Dubowitz Syndrome Parent Support. PO Box 173, Wheatland, IN 47597. (812) 886-0575.

WEBSITES

Dubowitz Syndrome Information and Parent Support. <http://www.dubowitz.org/> (20 April 2001).

"Dubowitz Syndrome." Online Mendelian Inheritance in Man. <http://www.ncbi.nlm.nih.gov/htbin-post/Omim/dispmim?223370> (20 April 2001).

Paul A. Johnson