SMARCAL1/HARP is an annealing helicase that functions in the repair and restart of damaged DNA replication forks and has been linked to AR Schimke immuno-osseous dysplasia (SIOD), which can cause T-cell immunodeficiency, but is also accompanied by short stature and other phenotypes (36). The gene discussed is SMARCAL1; the disease is Schimke immuno-osseous dysplasia.