This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Pediatrics
Which one of the following lysosomal storage disorder is associated with mental retardation? 
Select and explain. 
A. Metachromatic leucodystrophy, B. Fabry's disease, C. Tay Sach's disease, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: (D) All of the above# Metachromatic leukodystrophy (MLD, or Arylsulfatase A deficiency) is a lysosomal storage disease which is commonly listed in the family of leukodystrophies. Leukodystrophies affect the growth and/or development of myelin, the fatty covering which acts as an insulator around nerve fibers throughout the central and peripheral nervous systems. It involves sulfatide accumulation.> Like many other genetic disorders that affect lipid metabolism, there are several forms of MLD, which are late infantile, juvenile, arid adult.> Children with the juvenile form of MLD (onset between 3-10 years of age) usually begin with impaired school performance, mental deterioration, and dementia and then develop symptoms similar to the late infantile form but with slower progression.> Age of death is variable, but normally within 10 to 15 years of symptom onset although some juveniles can live for several decades or longer after onset.> Tay-Sachs disease (abbreviated TSD, also known as GM2 gangliosidosis or Hexosaminidase A deficiency) is an autosomal recessive genetic disorder.> In its most common variant, known as infantile Tay-Sachs disease, it causes a relentless deterioration of mental and physical abilities that commences around six months of age and usually results in death by the age of four.> Fabry disease (also known as Fabry's disease, Anderson.> Fabry disease, angiokeratoma corporis diffusum and alpha-galactosidase A deficiency) is a rare X-linked recessive (inherited) lysosomal storage disease, which can cause a wide range of systemic symptoms.Full body or localized pain to the extremities (known as acroparesthesia) or Gl tract is common in patients with Fabry disease.Kidney complications are a common and serious effect of the disease; renal insufficiency and renal failure may worsen throughout life.> Cardiac complications occur when glycolipids build up in different heart cells; heart related effects worsen with age and may lead to increased risk of heart disease.> Hypertension (high blood pressure) and cardiomyopathy are commonly observed.mental retardation is rare presentation