True regarding galactosemia
**Core Concept**
Galactosemia is a rare genetic disorder characterized by the inability to metabolize the sugar galactose, which is a component of lactose in milk. This condition leads to the accumulation of toxic byproducts, causing various systemic complications.
**Why the Correct Answer is Right**
Galactosemia is caused by a deficiency of the enzyme galactose-1-phosphate uridyltransferase (GALT), which is essential for the conversion of galactose-1-phosphate to UDP-galactose. Without this enzyme, galactose-1-phosphate accumulates and is converted to galactitol, leading to osmotic damage in various tissues. This condition is often diagnosed through a newborn screening test, which detects elevated levels of galactose-1-phosphate in the blood.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the primary enzyme deficiency responsible for galactosemia.
**Option B:** This option is incorrect because it mentions a different enzyme, galactokinase, which is involved in a different condition, galactosemia type II.
**Option C:** This option is incorrect because it does not accurately describe the primary metabolic block in galactosemia.
**Option D:** This option is incorrect because it does not provide a clear or accurate description of the condition.
**Clinical Pearl / High-Yield Fact**
It's essential to note that galactosemia can be managed through a strict lactose-free diet, which allows for the prevention of toxic byproduct accumulation and subsequent tissue damage.
**Correct Answer: B. Galactokinase deficiency leads to galactosemia type II.