| An immunodeficiency disorder with onset in infancy that leads to recurrent, severe infections of the respiratory tract. Infections are most frequently caused by rhinovirus. Respiratory syncytial virus and the influenza virus may also cause recurrent infections. Infection may require hospital admission and repeated infection can lead to chronic lung disease. Infections usually become less frequent with maturity. Caused by mutations in the IFIH1 gene, which provides instructions for making the MDA5 protein. Deficiency of MDA5 protein activity reduces interferon production in response to RNA-containing viruses. The inheritance pattern is unclear. In some cases, the condition seems to follow an autosomal recessive pattern, in other cases it appears that the condition is inherited in an autosomal dominant pattern. |
