Interstitial lung disease in an adolescent child associated with a novel STAT5B mutation-a case report

STAT5B protein is an important component of signalling pathway for growth hormone and IL-2 mediated responses. Mutation in STAT5B gene has been reported to be associated with growth hormone insensitivity, immunodeficiency and autoimmunity. Chronic pulmonary involvement is also one component of the disorder. We describe a case an adolescent girl who suffered with poor growth and loose stools since 1 year of age and was subsequently diagnosed with celiac disease and hypothyroidism. She developed features of interstitial lung disease (ILD) which were progressively worsening. Common causes of ILD were ruled out on investigations. She underwent whole exome sequencing and found to be positive for a novel mutation in STAT5B gene on exon 16. On further evaluation, she had growth hormone insensitivity and CD8 cell deficiency. This case highlights that in a child with chronic pulmonary involvement with features suggestive of growth hormone insensitivity, immunodeficiency and autoimmunity, evaluation for STAT5B mutation should be thought of.