Genealogic, clinic and laboratorial studies have been done, including serum phenylalanin.
Aron J. Diament, Antonio B. Lefèvre 1967, 'Fenilcetonúria: estudo clínico e mediante biópsia cerebral Phenylketonuria: clinicaland cerebral biopsy studies', Arquivos de Neuro-Psiquiatriahttp://www.scielo.br/scielo.php?script=sci_arttext&pid=S0004-282X1967000100001. Retrieved from DOAJ CC BY 4.0 (https://creativecommons.org/licenses/by-sa/4.0/legalcode)