Background: Mitochondrial diseases are a group of disorders caused by dysfunctional organelles that generate energy for our body. Mitochondria small double-membrane organelles found in every cell of the human body except red blood cells. Mitochondrial diseases are sometimes caused by mutations in the mitochondrial DNA that affect mitochondrial function. Other mitochondrial diseases are caused by mutations in genes of the nuclear DNA, either as Autosomal recessive or Autosomal dominant inheritance pattern whose gene products are imported into the mitochondria (mitochondrial proteins) as well as acquired mitochondrial conditions. We describe a clinical presentation of a patient with an autosomal recessive mitochondrial disease due to a homozygous mutation in the nuclear gene, NDUFV1 gene (OMIM: 618225).

Case presentation: In the present study, we report 36 months old girl from Saudi origin product of consanguineous marriage. With the clinical presentation of failure to gain normal developmental milestones, neuromotor regression, frequent attacks of the unexplained decreased level of consciousness and encephalopathy associated with central hypoventilation. There is a strong family history of similar presentation with early childhood deaths in two other siblings with no healthy kids for the couple. The girl evaluated thoroughly to reach a specific diagnosis, including clinical, radiological and biochemical work-up. However, we got an explanation for this phenotype through molecular genetic testing and couple referred for the Preimplantation Genetic Diagnosis.

Result: The constellation of clinical presentation and radiological finding confirmed by a Molecular test showed a homozygous missense mutation c. 1268C>T p. (Thr423Met) in the NDUFV1 gene (OMIM: 618225) which is consistent with autosomal recessive mitochondrial disease.