We studied the scientific literature and disease guidelines in order to summarize the clinical utility of the genetic test for Mendelian cataract (MC). MC is caused by variations in the AGK, BFSP1, BFSP2, CHMP4B, CRYAA, CRYAB, CRYBA1, CRYBA2, CRYBA4, CRYBB1, CRYBB2, CRYBB3, CRYGC, CRYGD, CRYGS, EPHA2, EYA1, FYCO1, FOXE3, FTL, GALK1, GCNT2, GJA3, GJA8, HSF4, LEMD2, LIM2, LSS, MAF, MIP, NHS, PITX3, PAX6, SIPA1L3, SLC16A12, TDRD7, UNC45B, VIM, VSX, and WFS1 genes. The overall prevalence of congenital forms is 71 per 100 000, whereas there is insufficient data to determine the prevalence of the juvenile and age-related forms. Clinical diagnosis is based on clinical findings, age of onset, family history, ophthalmological examination and slit-lamp examination. The genetic test is useful for confirming diagnosis, and for differential diagnosis, couple risk assessment and access to clinical trials.