TSPYL6 (Testis-specific Y-encoded-like protein 6) is a 410 amino acid member of the nucleosome assembly protein (NAP) family. TSPYL6 is believed to be similar to Testis-specific Y-encoded protein 1 in form and function. The gene that encodes TSPYL6 is found on chromosome 2 which consists of 237 million bases encoding over 1,400 genes and making up approximately 8% of the human genome. A number of genetic diseases are linked to genes on chromosome 2. The lipid metabolic disorder sitosterolemia is associated with ABCG5 and ABCG8. An extremely rare recessive genetic disorder, Alström syndrome is due to mutations in the ALMS1 gene.