PITX3 and early-onset non-syndromic cataract: Research on hereditary congenital cataracts led to the identification of several classes of candidate genes [2] that encode proteins such as the crystalline proteins (CRYAA, CRYAB, CRYBA1/A3,CRYBB1, CRYBB2, CRYBB3, CRYGC, CRYGD, and CRYGS) [3,4], the gap junction protein [5], major intrinsic protein (MIP/MIP26) [6], lens integral membrane protein 2 (LIM2/MP19), the beaded filament protein (BFSP2) [7], paired-like homeodomain transcription factor 3 (PITX3) [8], heat shock protein (HSF4) [9], and galactokinase [10].