ICF2 syndrome is a rare congenital disorder characterized by immunodeficiency, facial dysmorphism, and mental retardation. Cytogenetic defects arising from hypermethylation are seen in chromosome 1, 9, and 16 among affected patients . Although the T and B lymphocyte count remains normal, variable gamma globulin levels cause recurrent infections in ICF2 patients, which can especially be fatal during childhood.

With only 50 reported cases worldwide,  ICF syndrome has a prevalence of 1 in 1,000,000. Treatment plan for ICF patients usually consist of intravenous infusion of immunoglobulins or bone marrow transplantation.

ICF2 follows an autosomal recessive inheritance pattern. Mutations in ZBTB24 (Zinc Finger and BTB Domain Containing 24) gene are known to cause ICF2. The protein encoded by ZBTB24 is involved in hematopoietic progenitor cell differentiation and transcriptional regulation. Its role in BMP2 signaling pathway is considered to be associated with the developmental delay observed in ICF2 patients.