Which statement about galactosemia is true?
- Disease effects are limited to the eye.
- Cataracts are inevitably progressive.
- It can result from a defect in galactokinase or galactose-1-P uridyl transferase.
- It can lead to an accumulation of galactose in the lens, forming a snowflake cataract.
Explanation
Galactosemia is an autosomal recessive inborn error of metabolism affecting the conversion of galactose to glucose caused by a defect in galactokinase, UDPgalactose-4-epimerase, or galactose-1-P uridyl transferase (most common). Excess galactose accumulation in body tissues with subsequent conversion to galactitol leads to the classic oil-droplet cataract, liver dysfunction, and mental deficiency within the first few weeks of life. If left untreated, it is fatal. Three-quarters of patients develop cataracts because the nucleus and deep cortex become increasingly opacified. In some cases, early cataract formation can be reversed with dietary intervention.