2) Severe Combined Immunodeficiency Disorder (SCID)
It is an inherited X-linked disorder. The differentiation of T and B lymphocytes is hindered. So the immune system is debilitated and reduced to the state of its non-existence as the persons with this syndrome easily fall prey to viruses, harmful bacteria and fungi with negligible or no positive defense mechanism against such foreign bodies. Studies reveal that babies die even within 2-3years of their age. In addition to the defects in T and B lymphocytes, dearth or absence of Adenosine Deaminase (ADA) leaves the affected persons to succumb to the harmful germs at a faster pace.