Normal allele: GG
Breakage increases the likelihood of homocystinuria, which is insensitive to vitamin B6.
Polymorphism rs121964972 is related to topics like this:
Research and publications:
12686134 Structural insights into mutations of cystathionine beta-synthase.
22267502 Surrogate genetics and metabolic profiling for characterization of human disease alleles.
28583326 Cystathionine β-synthase deficiency: Of mice and men.