Thymic hypoplasia is a condition where the thymus is underdeveloped or involuted. Causes There are various causes of thymic hypoplasia such as 22q11.2 deletion syndrome, CHARGE syndrome, Nude/SCID and otofaciocervical syndrome type 2 (OTFCS2), and ataxia telangiectasia. References External links Noninfectious immunodeficiency-related cutaneous conditions