In contrast, the recessive mutations are located in hydrophobic repeats (HR-A/B) or downstream of the hydrophobic repeat, important for a trimeric formation and transcriptional activation of HSF4.[33] HSF4 mutant alleles responsible for dominant and recessive cataracts reveal a distinct location pattern, suggesting that a single mutant allele in the DNA binding domain is sufficient for cataractogenesis, whereas, homozygous mutant alleles residing outside of DNA binding domain are required for cataract phenotype. The gene discussed is HSF4; the disease is cataract.