The signs and symptoms of spondylocostal dysplasia can vary greatly from one person to another, even among members of the same family. Affected individuals have abnormalities in the development of the spine and ribs.
The bones of the spine (vertebrae) may be fused together or misshapen. Sometimes, they are underdeveloped and wedge-shaped (hemivertebrae). Multiple vertebrae are always affected, usually at least 10 segments in a row (contiguously). The ribs may be fused together, misaligned, broadened, split or forked (bifid), and sometimes some of the ribs are missing. Boys have an increased risk of developing inguinal hernia, a condition characterized by protrusion of parts of the large intestine through an opening in the abdominal wall near the groin.
The trunk, which is the part of the body that extends from the neck to the abdomen, may be disproportionately smaller in comparison to their height. In addition, affected individuals may be shorter than would otherwise be expected for their age and gender (Short stature). Affected individuals may have a Short neck with limited mobility. Some individuals have abnormal sideways curvature of the spine, a condition called scoliosis. Scoliosis is usually mild, but, in rare instances, can be severe. Scoliosis usually does not get worse, but should be carefully followed with spine x-rays
Because of the malformation of the spine and ribs, the lungs of affected individuals may not be able to grow and develop properly. This is known as thoracic insufficiency syndrome. Affected infants and children cannot expand their chests sufficiently with causes reduced lung capacity, which means the lungs can hold less air than they normally would. Consequently, they can have difficulties breathing and experience repeated respiratory infections. Breathing problems are usually mild or moderate, but sometimes can become life-threatening and be fatal. Some children may develop High blood pressure of the pulmonary artery, which is the main artery that delivers blood to the lungs (pulmonary hypertension). Pulmonary hypertension is a chronic and, if not treated, life-threatening complication. Reduced lung capacity also increases the risk of Heart failure another life-threatening complication.
Despite the potential for serious complications, most individuals with spondylocostal dysplasia live until adulthood. They may experience chronic back pain. Intelligence is usually unaffected, and neurological complications are rare.
Researchers are studying spondylocostal dysplasia to determine whether there are any genotype-phenotype correlations. Genotype is the distinct set of genes a person carries. Phenotype refers to the observable characteristics of a person. People with an altered LFNG gene usually have the most severe shortening of the spine. People with an altered HES7 gene have improper separation (malsegmentation) of the bones of the entire spine. People with an altered DLL3 gene usually (but not always) have mild scoliosis that does not require surgical intervention.