All mutations are not detected – why about 2% are missing is not known yet. Besides disease mutations a number of benign changes, called polymorphisms may be detected. They can also be diagnostically relevant in a family. Classification of most mutations is straight forward, while some may require additional evaluation. Is a polymorphism really a tolerated change or can it cause disease.

Most mutations occur only in that particular family, but the same type of mutation may occur several times, and some areas of the gene are more likely to mutate. A few mutations have been found in more families and a single mutation is regarded as common in Menkes boys. About 700 different mutations are known.

When reporting case stories in medical literature, it is important to include genetic analyses to be able to correlate symptoms and genetic changes. Unfortunately molecular investigations are not available in all countries.

When a mutation is detected it may be used to check further pregnancies in the family, and the mother and sisters can be carrier tested. A significant proportion of the mothers are not gene carriers, but the mutation has occurred as a new mutation in the Menkes patient or in a group of the mothers germ cells. When analysing a blood sample, this will not be detected. Therefore prenatal testing in new pregnancies is recommended even if a mother is a non-carrier, and sisters of the patient should still be tested.