The respiratory presentation of severe combined immunodeficiency in two Mennonite children at a tertiary centre highlighting the importance of recognizing this pediatric emergency.

Severe combined immunodeficiency (SCID) is considered to be a pediatric emergency, with respiratory distress being the most common presenting symptom. The authors present two cases of SCID in children <4 months of age with respiratory distress at a tertiary care centre due to a recently described homozygous CD3 delta mutation found only in the Mexican Mennonite population. Failure to respond to broad-spectrum antibiotics prompted investigation for possible SCID.