Two Turkish patients with Primary Coenzyme Q10 Deficiency-7: case report and literature review

Primary Coenzyme Q10 Deficiency-7 (OMIM 616276) results from bi-allelic pathogenic variants in the COQ4 gene. Common clinical findings include hypotonia, seizures, respiratory distress, and cardiomyopathy. In this report, we present two patients diagnosed with Primary Coenzyme Q10 Deficiency-7 along with a review of previously published cases, with the aim being to provide a better understanding of the clinical and laboratory manifestations of the disease.

A 3-month-and-22-day-old male was admitted to our outpatient clinic due to poor feeding and restlessness. He was born following an uneventful pregnancy to a nonconsanguineous marriage. A physical examination revealed hypotonia, a dolichocephaly, periorbital edema, and long eyelashes. Blood tests revealed metabolic acidosis and elevated serum lactate levels, while the genetic analysis revealed a variant previously reported as pathogenic, c.437T>G (p.Phe146Cys), in the COQ4 gene. Genetic tests were also conducted on both mother and father, and it revealed heterozygous variant, 0.437T>G (p.Phe146Cys), in the COQ4 gene. As a result of these findings, the patient was diagnosed with neonatal encephalomyopathy-cardiomyopathy-respiratory distress syndrome (Primary Coenzyme Q10 Deficiency-7). A 1-year-old male was admitted to our clinic with complaints of hypotonia, seizures, and feeding difficulties. He was born following an uneventful pregnancy to a nonconsanguineous marriage. On his first day of life, he was admitted to the neonatal intensive care unit due to poor feeding and hypotonia. A physical examination revealed microcephaly, a high palate, poor feeding, weak crying, hypotonia, bilateral horizontal nystagmus, and inability to maintain eye contact. Laboratory findings were within normal limits, while a whole exome sequencing analysis revealed a homozygous variant previously reported as pathogenic, c.458C>T (p.A153V), in the COQ4 gene. The patient was diagnosed with Primary Coenzyme Q10 Deficiency-7.

Primary Coenzyme Q10 Deficiency-7 should be considered in the differential diagnosis of infants presenting with neurological and dysmorphic manifestations.