Checking the family
If the confirmatory tests lead to a definite diagnosis of Lesch-Nyhan disease, it becomes very important to check family members as a third step. At a minimum, the child’s mother should be checked. Because of the way Lesch-Nyhan disease is inherited, the disease shows up in males but stays silently hidden in females. A mother who carries the disease will seem completely normal. Only genetic or metabolic testing will uncover it. If she carries the disease, she could pass it along to her next child.
If the mother turns out to be a silent carrier, it becomes important to check other female members of the family to make sure they are not carriers too. This includes all of the child’s sisters and some of his aunts too. It is not necessary to check everyone. A genetic counselor can help to determine who needs to be checked.