Furthermore, two cases of isolated FSH deficiency with normal FSH-β gene and usual LH/T levels [first, two young men having moderate testicular hypotrophy (75, 76), second, a 19 years old boy being homozygous for a novel silent polymorphism (G/T substitution) in FSH-β promoter (77),] show severe sperm abnormalities to complete azoospermia respectively. Here, PLOD1 is linked to Azoospermia.