Weismann-Netter-Stuhl syndrome is an extremely rare inherited skeletal disorder characterized by the abnormal development of bone (osseous dysplasia). Affected individuals exhibit bowing of the long portions (shafts) of the shinbone (tibia) and the outer, smaller bone of the leg below the knee (fibula). In some individuals, other bones may also be affected, such as the ribs, pelvis, spinal column, and/or bones in the arms. The primary characteristic of Weismann-Netter-Stuhl syndrome is short stature (dwarfism). In most cases, this disorder is thought to be inherited as an autosomal dominant trait.

Although researchers have been able to establish a clear syndrome with characteristic or “core” symptoms, much about the disorder is not fully understood. Several factors including the small number of people identified with this disorder, the lack of large clinical studies, and the underlying cause of the disorder being unknown prevent physicians from developing a complete picture of associated symptoms and prognosis. Therefore, it is important to note that affected individuals may not have all the symptoms discussed below. Parents should talk to their children’s physicians and medical team about their specific case, associated symptoms and overall prognosis. The major physical characteristics of Weismann-Netter-Stuhl syndrome include Short stature and bowing of the front (anterior) of the long portions (shafts) of the shinbone (tibia) and the smaller bone of the leg below the knee (fibula). Sometimes the long bone of the thigh (femur) is bowed. Many affected individuals do not have any major functional limitations, and a diagnosis of Weismann-Netter-Stuhl syndrome may not be made until adolescence or adulthood because of the lack of serious complications associated with this disorder. Usually both legs are affected (bilateral). In extremely rare instances, only one leg is affected (unilateral).

Along with the characteristic bowing of the tibia and fibula, affected individuals may also exhibit bowing of the sides (lateral bowing) of the thigh bones (femur) and/or outward curvature of the tibia (saber shins). Benign (non-cancerous) overgrowths of cartilage called exostoses may affect the tibias. Additional bones may also be affected including the ribs and pelvis.

Affected individuals may also exhibit bowing of certain bones in the forearms (i.e., ulna and radius), malformation of a part of the hip bone (ilium), improper development of bone toward the bottom of the spinal column (horizontal sacrum), widening of the marrow cavities inside bones, and/or Thickening of the outer layers (cortexes) of the long bones (diaphyseal dysplasia). Sometimes, a hip deformity in which the thigh bone is angled toward the center of body (coxa vara) is present.

In addition, some affected individuals may exhibit a sideways curvature of the spine (scoliosis), an inward curvature of the back (lordosis) so that the back curves into the body, and/or a front-to-back curvature of the spine (kyphosis) so that the upper back is rounded. Most affected individuals begin to walk later than is normally expected, however, the reason for this delay is not understood.

There have been reports of intellectual disability in some children as well as an enlarged thyroid (goiter) and low levels of circulating red blood cells (anemia). However, some researchers believe that these findings may be coincidental and not features of Weismann-Netter-Stuhl syndrome.

The exact, underlying cause of Weismann-Netter-Stuhl syndrome is unknown. Sometimes, the disorder runs in families. Researchers believe it is most likely caused by a change in a gene. However, no genes have been identified to be associated with the disorder. Genes provide instructions for creating proteins that play a critical role in many functions of the body. When a mutation of a gene occurs, the protein product may be faulty, inefficient, or absent. Depending upon the functions of the protein, this can affect many organ systems of the body.

Although no altered genes have been identified to be associated with Weismann-Netter-Stuhl syndrome, researchers believe that the disorder is inherited in an autosomal dominant manner. Most genetic diseases are determined by the status of the two copies of a gene, one received from the father and one from the mother. Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary to cause a particular disease. The abnormal gene can be inherited from either parent or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from an affected parent to an offspring is 50% for each pregnancy. The risk is the same for males and females.

The treatment of Weismann-Netter-Stuhl syndrome is directed toward the specific symptoms that are apparent in each individual. Genetic counseling will be of benefit for affected individuals and their families. A supportive team approach for children with Weismann-Netter-Stuhl syndrome may be helpful. Such a team approach may include physical therapy and other medical, social, or vocational services.

For many people, the skeletal abnormalities do not disturb the functions of the legs or only mildly affect function. One journal article recommended surgical intervention for Weismann-Netter-Stuhl syndrome (Gupta 2014). However, if the abnormalities of the legs are not causing any functional problems, then surgery is not necessary. Decisions concerning treatment can vary for each affected individual depending on several factors including their age, severity of the skeletal malformation and misalignment, an individual’s overall health, patient preference and other appropriate factors.

Weismann-Netter-Stuhl syndrome is an extremely rare skeletal disorder that affects males and females in equal numbers. Approximately 70 people have been reported in the medical literature since the disorder’s original description in 1954. However, because rare disorders like Weismann-Netter-Stuhl syndrome often go unrecognized, these disorders are under-diagnosed, making it difficult to determine the true frequency in the general population.