The impact of genomics in clinical medicine has been significant in recent years. Up to 2012, more than 3,000 genetic conditions have been implicated in clinical medicine. Today, with the new methodology of genome sequencing (next-generation sequencing (NGS) and comparative genomic sequencing (CGH), Mendelian conditions have been identified, as well as their role in genetic variations and polygenetic multifactorial disorders that affect the clinical prognosis and response to treatment.The integration of these diagnostic approaches in clinical practice requires an understanding of the basic principles of heredity, genome organization and molecular genetics. Generally, these conditions are single-gene disorders (also known as monogenic disorders), meaning that a single gene mutation is responsible for the disease.The genetic screening test analyzes hundreds of mutations for recessive genetic diseases. This test informs whether or not such mutations are present, which may lead to large-scale genotyping in children using multiple molecular probes.We report two cases of young adult women with symptoms and multiple medical consultations with disease recurrence and uncertain diagnosis, who underwent genetic testing and were determined to be carriers of heterozygous and homozygous mutant ethylmalonic aciduria and methylenetetrahydrofolate reductase deficiency, which could be responsible, in part, for their confusing symptoms.

A combinação da Aciduria etilmalónica e a homocistinuria são desordens do metabolismo herdados com um amplo espectro de manifestações clínicas que se podem apresentar desde a infância até os adultos maiores. No entanto, com a detecção precose destas doenças, no período neonatal, se teria a oportunidade de melhorar a qualidade de vida dos pacientes afetados.