Schwartz-Jampel syndrome (SJS) is a rare, inherited condition of the skeletal and muscle systems that causes short stature, joint limitations, and particular facial features.
A child born with SJS Type 1A may show no outward signs of the condition at birth. Over the following one to three years, progressive myotonia of the muscles and resulting joint contractures develop. The typical bone problems become obvious and growth in height slows down. These symptoms are evident at birth in children with SJS Type 1B. The following descriptions apply to both SJS Type 1A and Type 1B. However, each person with SJS may be affected to a different degree and their kinds of symptoms may vary.
The diagnosis of SJS Type 1A or Type 1B is made mainly by the presence of the symptoms described above. There is no specific biochemical or muscle testing that confirms a suspected diagnosis. Although research studies have identified mutations in the HSPG2 gene in some families, widespread genetic testing is not clinically available as of the year 2001. Such genetic mutations may be unique to each family and therefore may not be found in other persons affected with SJS. Several different studies may be performed to determine the type and severity of muscle disease when considering a diagnosis of SJS. This may include a muscle biopsy that samples a piece of muscle and examines the appearance of the muscle cells. A muscle biopsy may appear normal or it may show signs of myopathy. A particular chemical, called creatine kinase, can be measured in a person's blood. Very high levels of creatine kinase usually indicate the presence of muscle disease or wasting. An electromyogram (EMG) is a test that measures the electrical currents made within an active muscle. The EMG pattern is usually abnormal in persons with SJS. These tests will confirm the presence of muscle disease but there are no specific changes in any of them that are unique to SJS. The following are some abnormalities of the bones that are frequently noticed on x rays: * flat and irregularly formed vertebrae * deformity of the upper part of the thigh bone * a flattened joint socket where the hip and thigh bone meet * specific changes in the development of the bones in the hand * bowing of the long bones, especially the leg bones * curvature of the spine that causes a hunchback appearance Many of the symptoms of SJS are also present in other conditions and it is important to distinguish SJS from the following disorders: * Stuve-Wiedemann syndrome (which was previously called SJS Type 2 until it was determined that they were the same condition) * Freeman-Sheldon syndrome (also known as whistling face syndrome) * Marden-Walker syndrome * Kniest dysplasia * Seckel syndrome * myotonic dystrophy * the mucopolysaccharidoses
Individuals with SJS can live well into adulthood despite progressive disability but the average life expectancy is unclear. They are usually wheelchair-bound by their teenage or young adult years. Although puberty development may be normal, no reports have been made of an individual with SJS fathering children or carrying a pregnancy. SJS Type 1B may be fatal in the newborn period due to serious respiratory and feeding problems. As the muscles in the face and neck may be very tight, it can be difficult to place a tube down the throat (intubation) to allow a baby to breathe. Feeding may be a continuous struggle due to problems with or an inability to swallow. Both types of SJS cause persons to be more prone to develop chest infections and pneumonia. There is also an increased risk for complications from anesthesia, specifically malignant hyperthermia (MH). MH is an abnormal chemical reaction in the body to the use of some anesthesia medications. It causes high fevers, breathing difficulty, rigid muscles and general serious illness. This condition may be life threatening.
There is not a cure for SJS. The treatment involves managing the symptoms of the condition as they develop and supporting the needs of the individual as the disability progresses. Several medical specialists may monitor a person with SJS for particular symptoms or complications. An orthopedic doctor manages the abnormal bone development and may offer surgical options for treatment of hip dislocation, scoliosis, or bone curvature. An ophthalmologist monitors eye problems such as nearsightedness and cataracts, for which glasses and surgery may be available. Cosmetic repair of blepharophimosis by plastic surgery may also be considered.