<unk>  is a rare immune disorder in which a child is born without a thymus – an organ that plays a critical role in helping the body learn to fight infections. Children impacted by this disease typically die within the first two years of life and may have repeated, often life-threatening infections because they lack adequate working T cells (a kind of infection-fighting white blood cell).
Congenital athymia
Euthymia 
Dysthymia
Cyclothymia
Minor depressive disorder
Myokymia
Atypical depression
Disruptive mood dysregulation disorder