Congenital cataracts cause 10 to 30% of all blindness in children, with one-third of cases estimated to have a genetic cause (summary by Bu et al., 2002). Mutations in the HSF4 gene have been found to cause multiple types of cataract, which have been described as infantile, lamellar, zonular, nuclear, anterior polar, stellate, and Marner-type. The preferred title for this entry was formerly 'Lamellar Cataract,' with 'Cataract, Marner Type; CAM; CTM' an included title.

A cataract which affects the layer of the lens surrounding the nucleus, i.e., the lens cortex. It is identified by its unique wedge or spoke appearance.

A nuclear cataract is an opacity or clouding that develops in the lens nucleus. That is, a nuclear cataract is one that is located in the center of the lens. The nucleus tends to darken changing from clear to yellow and sometimes brown.