TBX22 mutations are a frequent cause of non‐syndromic cleft palate in the Thai population

Mutations in the TBX22 gene underlie an X‐linked malformation syndrome with cleft palate (CP) and ankyloglossia. Its mutations also result in non‐syndromic CP in some populations. To investigate whether mutations in TBX22 play a part in the formation of non‐syndromic CP in the Thai population, we performed mutation analysis covering all the coding regions of the TBX22 gene in 53 unrelated Thai patients with non‐syndromic CP. We identified four potentially pathogenic mutations, 359G→A (R120Q), 452G→T (R151L), 1166C→A (P389Q), and 1252delG in four different patients. All mutations were not detected in at least 112 unaffected ethnic‐matched control chromosomes and had never been previously reported. R120Q and R151L, found in two sporadic cases, were located in the DNA binding T‐box domain. P389Q and 1252delG, found in two familial cases, were at the carboxy‐terminal region, which has never been described. Our study indicates that TBX22 mutations are responsible for a significant proportion of Thai non‐syndromic CP cases confirming its importance as a frequent cause of non‐syndromic CP across different populations.