SYCP2 and familial isolated pituitary adenoma: However, the 20q13.33 locus contains synaptonemal complex protein 2 (SYCP2), a cohesion complex gene, while other cohesion complex genes were also found amplified in somatotroph adenomas:SYPC1 on chromosome 1p13.2 was amplified in 11/20 somatotroph samples and RAD21 cohesin complex component like 1 (RAD21L1) on chromosome 20p13 was amplified in 4/20.