Overview of repeats
A polyalanine expansion in the FOXL2 gene was discovered by Nallathambi et al. (2007) in one Indian family diagnosed with the blepharophimosis, ptosis, and epicanthus inversus syndrome (BPES). The allele is highly conserved and has 14 repeats of alanine. They found a homozygous 5 repeat expansion in two individuals of the family that resulted in a stretch of 19 residues of alanine long, demonstrating recessive allele behaviour (Nallathambi et al., 2007). However, other research has shown patients with BPES who have heterozygous alanine expansions and also longer, such as alleles with 24 alanine repeats present (De Baere et al., 2001; De Baere et al., 2003).