Marchegiani et al. [15] identified heterozygosity for a missense mutation in the TWIST2 gene (E75K) in ten patients with AMS from seven unrelated families, as well as heterozygosity for missense mutations (E75Q and E75A) and a 6-bp duplication at codons 77 and 78 in the TWIST2 gene, in eleven patients from nine unrelated families with BSS [15]. Here, TWIST2 is linked to Barber-Say syndrome.