What are the possible genotypes of the parents?

The genotype of a male with Adrenoleukodystrophy would be X^r  Y.

The genotype of a female with Adrenoleukodystrophy would be X^r X^r

The genotype of a female carrier would be X^r X.

A carrier carries one copy of the altered gene. In females (who have two X chromosomes), a mutation must usually be present in both copies of the gene to cause the disorder. In some cases, however, females who are carriers of a gene mutation on the X chromosome will exhibit signs and symptoms of a disorder beginning in adulthood.

For a female to get Adrenoleukodystrophy, the father must have the disease and the mother must be at least a carrier or have it herself. All a male needs to get Adrenoleukodystrophy is the mother to be a carrier of have it herself. What is interesting about X linked recessive disease is that a father cannot pass on the disease to a son, and a diseased female must have had a diseased father.

http://www.medic8.com/genetics/xlinked-adrenoleukodystrophy.htm