If my child is diagnosed with AADC will the whole family have to have a test?

AADC deficiency is an autosomal recessive condition. Everybody has one AADC gene and each AADC gene is made of two parts (alleles).  One allele comes from one parent and the other comes from the other parent. In a child affected with AADC deficiency both alleles have a mutation, one mutation came from the mother and the other from the father.  This means that the mother and father have one normal allele and the other allele carries a mutation –they are known as heterozygote carriers for AADC deficiency. This does not affect AADC function in the parents. If the parents have another child, there is a 25% chance that the child will be affected by AADC deficiency, a 50% chance that the child will be a heterozygote carrier and a 25% chance that the child will have a completely normal AADC gene. See the link ‘is AADC and inherited disease’.

It is up to the parents to decide if they wish to know if other family members are heterozygote carriers or completely unaffected.

Testing for carrier status can be done by measuring AADC activity in blood – see the link ‘how is AADC diagnosed’ for more information about this test.