TMEM166, also known as FAM176A (family with sequence similarity 176, member A), is a 152 amino acid protein encoded by a gene mapping to human chromosome 2. The second largest human chromosome, 2 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. Harlequin icthyosis, a rare and morbid skin deformity, is associated witHuman, Mouseutations in the ABCA12 gene.