T-B+NK+ SCID has recently been described in another rare AR disorder, otofaciocervical syndrome type 2 (OTFCS2), which is caused by PAX1 deficiency and is characterized by syndromic features, including facial dysmorphism, ear and vertebral anomalies (119, 120). The gene discussed is PAX1; the disease is otofaciocervical syndrome 2.