• Identified four novel PITX2 variants in Chinese ARS families, including two frameshift, one nonsense, and one splice-site mutation.
• All variants co-segregated with the disease phenotype in an autosomal dominant pattern, with two occurring de novo.
• The variants are absent from population databases, confirming their rarity and likely pathogenicity.
• This study expands the mutational spectrum of PITX2 and provides a basis for genetic counseling and functional studies.