TBX1 heterozygous mono-allelic mutations have been associated with conotruncal anomaly face syndrome, thymic hypotrophy, parathyroid dysfunction, and deafness in a small sample of individuals without broader 22q11.2 deletion, providing a further suggestion of a key role in individuals with broader 22q11.2 deletion [225]. The gene discussed is TBX1; the disease is 22q11.2 deletion syndrome.