HSF1 and cataract: Cataract is a major cause of adult blindness and congenital cataract is a major cause of childhood blindness.1 At least 44 genetic loci and over 40 genes have been linked to congenital or early-onset cataract.2, 3, 4 Heat shock transcription factor 4 (HSF4) has been associated with isolated cataract5 and it belongs to the heat shock transcription factor family (including HSF1, HSF2, HSF3 and HSF4).