Arylsulfatase A Deficiency

Definition

Definition of Arylsulfatase A Deficiency
Metachromatic leukodystrophy (MLD) is a genetic disorder that affects nerves, muscles, other organs, and behavior. It slowly gets worse over time.

Symptoms

Symptoms of Arylsulfatase A Deficiency

1. Abnormal high muscle tone, abnormal muscle movements
2. Behavior problems
3. Decreased mental function
4. Decreased muscle tone
5. Difficulty walking
6. Feeding difficulties
7. Frequent falls
8. Inability to perform normal tasks
9. Incontinence
10. Irritability
11. Loss of muscle control
12. Nerve function problems
13. Personality changes
14. Poor school performance
15. Seizures
16. Speech difficulties, slurring
17. Swallowing difficulty

Causes

Causes of Arylsulfatase A Deficiency
MLD is usually caused by the lack of an important enzyme called arylsulfatase A. Because this enzyme is missing, chemicals called sulfatides build up in and damage the nervous system, kidneys, gallbladder, and other organs. In particular, the chemicals damage the protective sheaths that surround nerve cells.

The disease is passed down through families (inherited). You must get a copy of the defective gene from both your parents to have the disease. Parents can each have the defective gene, but not have MLD. A person with one defective gene is called a "carrier."

Diagnosis

Diagnosis of Arylsulfatase A Deficiency
Possible tests include:

1. Blood or skin culture to look for low arylsulfatase A activity
2. Blood test to look for low arylsulfatase A enzyme levels
3. CT scan
4. DNA testing for the ARSA gene
5. MRI
6. Nerve biopsy
7. Nerve velocity conduction studies
8. Urinalysis
9. Urine chemistry

Treatment

Treatment of Arylsulfatase A Deficiency
There is no cure for MLD. Care focuses on treating the symptoms and preserving the patient's quality of life with physical and occupational therapy.

Prognosis

Prognosis of Arylsulfatase A Deficiency
MLD is a severe disease that gets worse over time. Eventually people lose all muscle and mental function. Life span varies depending on what age the condition started, but the disease course usually runs 3-20 or more years.

Prevention

Prevention of Arylsulfatase A Deficiency
Genetic counseling is recommended if you have a family history of this disorder.