Rapid genome sequencing identifies novel variants in complement factor I

Complement factor I deficiency (CFID; OMIM #610984) is a rare immunodeficiency caused by deficiencies in the serine protease complement factor I (CFI). CFID is characterized by predisposition to severe pneumococcal infection, often in infancy. We report a previously healthy adolescent male who presented with respiratory failure secondary to pneumococcal pneumonia and severe systemic inflammatory response. Rapid genome sequencing (rGS) identified compound heterozygous variants in CFI in the proband, with a novel maternally inherited likely pathogenic variant, a single nucleotide deletion resulting in premature stop (c.1646del; p.Asn549ThrfsTer25) and a paternally inherited novel likely pathogenic deletion (Chr 4:110685580–110692197del).