The genetic disorder that is related with the lack of an enzyme that is necessary for the normal metabolism of phenylalanine is called Phenylketonuria. This happens in babies where they do are not able to break down phenylalanine in the body.
I fins that in helps to remember and implement suffixes, especially in regard to health care. The suffix of breast is -mastia. The suffix of without is a-. So the answer would be Amastia.
