short-rib thoracic dysplasia 18 with polydactyly

Short-rib thoracic dysplasia 18 with polydactyly is a multisystem skeletal disorder that is characterized by underdeveloped thoracic structures and limb abnormalities. Genetic alterations in the IFT43 gene are responsible for the condition, and it follows an autosomal recessive inheritance pattern. Affected individuals typically present at birth with distinct skeletal malformations, and the condition may be identified during infancy due to characteristic radiologic and clinical findings. Prevalence data are not well established for this condition.

The clinical presentation of this condition involves multiple organ systems, with the most prominent features affecting the skeletal system. Almost all individuals exhibit characteristic skeletal anomalies such as radial and ulnar bowing, platyspondyly, thoracic hypoplasia, micromelia, and other findings including short and missing ribs and vertebral wedging. Limb abnormalities are notable as both preaxial and postaxial polydactyly may be present, and additional features such as brachydactyly and decreased calvarial ossification have been observed in a subset of patients. Other manifestations that occur in 30 to 79% of cases include craniofacial features like hypertelorism, dolichocephaly, micrognathia, and transient findings such as cystic hygroma, hydrocephalus, ventriculomegaly, choroid plexus cysts, and intestinal malrotation. Not all individuals experience all of these features, and severity varies considerably.

This condition is caused by pathogenic variants in the IFT43 gene, which plays a critical role in intraflagellar transport necessary for normal skeletal and organ development. It is inherited in an autosomal recessive pattern, meaning that an individual must inherit two copies of the altered gene, one from each carrier parent, to be affected. As with many autosomal recessive conditions, there is a 25% recurrence risk in each pregnancy when both parents carry a mutation. Genetic counseling is recommended for families to better understand these implications and to discuss potential risks for future pregnancies.

Currently, management focuses on supportive care and symptom management since there are no treatments specifically approved for short-rib thoracic dysplasia 18 with polydactyly. Treatment is tailored to the individual and typically involves a multidisciplinary care team that may include pediatricians, orthopedic specialists, and other experts to address the various aspects of the condition. Long-term management includes regular surveillance to detect potential complications early, and genetic counseling is recommended to help families understand the condition and the inheritance pattern. Patients are encouraged to discuss all treatment options with their healthcare team to determine the most appropriate approach for their specific situation.

The long-term outlook for individuals with short-rib thoracic dysplasia 18 with polydactyly is highly variable, with outcomes that depend on the severity of skeletal involvement and the presence of additional complications. With current standards of care, many individuals benefit from improved management strategies and regular monitoring, and outcomes described in medical literature continue to evolve as standards of care improve. Families often find it helpful to connect with specialists experienced in managing multisystem conditions, and genetic counseling can provide further guidance on future family planning. It is important to recognize that not all individuals experience every feature, and the overall course of the condition may range from relatively stable to requiring ongoing supportive interventions.