Primary Ciliary Dyskinesia (CCDC39)
Primary ciliary dyskinesia (CCDC39-related) is an autosomal recessive disorder caused by pathogenic variants in the gene CCDC39. While this disorder may be seen in individuals of various ethnicities, it is most prevalent amongst Amish and Mennonite communities. In affected individuals, ciliary dysfunction results in chronic sinusitis and bronchiectasis, frequent bouts of pneumonia, and hearing loss associated with recurrent ear infections. Most infants require respiratory assistance in the first few weeks of life. Approximately half of all affected adult males are infertile due to sperm immobility. Situs inversus, a benign condition where the internal organs are found on the opposite side of the body, occurs in ~50% of affected individuals. Some patients have abnormal left-right axis patterning resulting in organ malformations, including the heart. These patients may have a poor prognosis. Individuals may have decreased life expectancy due to recurrent respiratory infections. No clear genotype-phenotype correlation has been established.
For information about carrier frequency and residual risk, please see the residual risk table.