▁the ▁experimental ▁stage ; ▁few ▁are ▁even ▁in ▁clin ical ▁tri als , ▁none ▁have ▁been ▁F DA ▁approved , ▁and ▁avail ability ▁in ▁clin ical ▁practice ▁may ▁be ▁years ▁or ▁even ▁a ▁de cade ▁or ▁more ▁away . ▁ ▁History ▁ ▁X - link ed ▁ag amm ag lob ul in emia ▁was ▁one ▁of ▁the ▁first ▁described ▁primary ▁imm un ode fic ien cies , ▁discovered ▁by ▁Og den ▁Br ut on ▁in ▁ 1 9 5 2 . ▁Primary ▁imm un ode fic ien cies ▁were ▁initially ▁class ified ▁in ▁ 1 9 7 0 ▁by ▁a ▁committee ▁of ▁the ▁World ▁Health ▁Organ ization . ▁At ▁the ▁time , ▁they ▁identified ▁ 1 6 ▁imm un ode fic ien cies . ▁By ▁ 1 9 9 8 , ▁the ▁number ▁had ▁reached ▁ 5 0 . ▁ ▁Disc overy ▁of ▁novel ▁gen etic ▁causes ▁of ▁inn ate ▁imm un ode fic ien cies ▁acceler ated ▁greatly ▁in ▁the ▁ 2 0 1 0 s ▁due ▁to ▁high - through put ▁DNA ▁sequ encing ▁techn ologies . ▁As ▁of ▁ 2 0 1 9 , ▁more ▁than ▁ 4 3 0 ▁have ▁been ▁categor ized . ▁ ▁See ▁also ▁Im mun ode fic iency ▁ ▁References ▁ ▁External ▁links ▁ ▁International ▁Union ▁of ▁Im mun ological ▁soci eties ▁( I UI S ) ▁ ▁Category : Im mun ode fic iency <0x0A> </s> ▁The ▁Republic ▁of ▁Ireland ▁national ▁fut sal ▁team ▁has ▁represented ▁the ▁Republic ▁of ▁Ireland ▁in ▁the ▁UEFA ▁F