A pediatric case report of recurrent chest infections and absent B cells associated with homozygous variation of uncertain significance in the ZNF699 gene

A 6-year-old boy was born at term via spontaneous vaginal delivery to consanguineous parents with an uneventful pregnancy. The patient has a history of recurrent chest infections, bronchial asthma, bilateral undescended testicles, a solitary right kidney, and microcytic anemia. Whole-genome sequencing was performed, revealing a homozygous variant of uncertain significance in the ZNF699 gene. Basic immunology tests revealed a normal reaction to the pneumococcal and diphtheria vaccines, as well as normal immunoglobulin levels. Flow cytometry of lymphocytes revealed normal T and NK cells, zero B cells, and a CD4/CD8 reversal ratio.