Primary Coenzyme Q10 Deficiency-7 and Pathogenic COQ4 Variants: Clinical Presentation, Biochemical Analyses, and Treatment

Clinical features and genotype in COQ4 associated hereditary spastic paraplegia: a case report and a literature reanalysis

INTRODUCTION

COQ4 mutation often leads to a fatal multi-system disease in infants. Recently, it was reported that the biallelic COQ4 variants may be a potential cause of hereditary spastic paraplegia (HSP). This study aims to describe the clinical features and genotype of the COQ4 associated hereditary spastic paraplegia (HSP).

METHODS

We reported a case of HSP with COQ4 variants, and a literature reanalysis was performed.

RESULTS

Three studies with a total of 1309 patients with HSP of unknown cause were included, and 13 (1%) patients were found to have biallelic COQ4 variants. Seven patients fulfilled pure HSP, and six patients fulfilled complicated HSP. The median age of these patients was 24 years (range 15 to 65 years), and the median year of disease onset was 14 years (range 1 to 55 years). The most common clinical manifestations were lower limb spasticity (100%), hyperreflexia (100%), Babinski sign (77%), reduced muscle strength (53.8%) cerebellar ataxia (23.1%), seizures (23.1%) and dysarthria (23.1%). Including our case, 16 different variants located in exon 2, exon 4, exon 5, exon 6, exon 7 and two introns of the COQ4 gene have been identified in patients with HSP. All started CoQ10 supplementation, but follow-up was reported in only one patient.

CONCLUSION

COQ4 variants were associated with childhood, adolescent, and adult onset HSP, which has a relatively mild course. The efficiency of CoQ10 supplement in patients with COQ4 associated HSP need to be classified in the future study.

The Spectrum of clinical manifestations in newborns with the COQ4 mutation: case series and literature review

Background

Coenzyme Q10 (CoQ10) plays an important role in the electron transport chain within the human mitochondrial respiratory chain. The manifestations of this deficiency exhibit a diverse range. This study investigates the clinical manifestations of primary coenzyme Q10 deficiency in neonates with the COQ4 mutation to improve the diagnosis of the disease and the prognosis through targeted treatment.

Methods

We report 4 patients with primary coenzyme Q10 deficiency by COQ4 variants in neonates. A comprehensive literature search and review for original articles and case reports with COQ4 mutation published from January 1989 to November 2023 was performed through Pubmed. We review clinical manifestations, diagnostic approaches, and treatment monitoring in these and 20 previously reported patients.

Results

Within the cohort of four cases examined, three females and one male were identified from two distinct families. Specifically, case 1 and 2 consisted of monoamniotic twins. Cases 3 and 4 were siblings. A comprehensive review of 20 cases involving neonatal-onset COQ4 mutation was conducted. Half of the cases are Chinese. There was no statistically significant difference in the mortality between Chinese (9/12, 75%) and other regions (11/12, 91.7%) (P = 0.27). The survival time for the 24 cases was 60.0 ± 98.0 days (95% confidence interval CI: 0-252.0 days). The incidence of prenatal abnormalities in preterm infants was significantly higher than that in full-term infants (66.7% vs. 16.7%, P = 0.02). Hyperlactatemia was one of the most common manifestations, accounting for 75% of cases (18/24). Twenty of the 24 cases were diagnosed by whole exome sequencing. Only 9 patients received exogenous coenzyme Q10 treatment, and all the 4 surviving patients received coenzyme Q10 supplementation.

Conclusion

The prognosis of COQ4 mutation in the neonatal period indicates a low survival rate and an poor prognosis. This may be due to the incomplete understanding of the mechanism of how COQ4 gene defects lead to coenzyme Q10 deficiency and why CoQ10 supplementation does not respond well to treatment. To improve the diagnostic rate, in addition to genetic testing, mitochondrial functional verification should be prioritized in southern China, where the incidence is relatively high. It will facilitate more in-depth mechanistic studies.

Biallelic variants in the COQ4 gene caused hereditary spastic paraplegia predominant phenotype

INTRODUCTION

Hereditary spastic paraplegias (HSPs) comprise a group of neurodegenerative disorders characterized by progressive degeneration of upper motor neurons. Homozygous or compound heterozygous variants in COQ4 have been reported to cause primary CoQ10 deficiency-7 (COQ10D7), which is a mitochondrial disease.

AIMS

We aimed to screened COQ4 variants in a cohort of HSP patients.

METHODS

A total of 87 genetically unidentified HSP index patients and their available family members were recruited. Whole exome sequencing (WES) was performed in all probands. Functional studies were performed to identify the pathogenicity of those uncertain significance variants.

RESULTS

In this study, five different COQ4 variants were identified in three Chinese HSP pedigrees and two variants were novel, c.87dupT (p.Arg30*), c.304C>T (p.Arg102Cys). More importantly, we firstly described two early-onset pure HSP caused by COQ4 variants. Functional studies in patient-derived fibroblast lines revealed a reduction cellular CoQ10 levels and the abnormal mitochondrial structure.

CONCLUSIONS

Our findings revealed that bilateral variants in the COQ4 gene caused HSP predominant phenotype, expanding the phenotypic spectrum of the COQ4-related disorders.

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

OBJECTIVES

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.

CASE PRESENTATION

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.

CONCLUSIONS

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

Metabolic etiologies in children with infantile epileptic spasm syndrome: Experience at a tertiary pediatric neurology center

OBJECTIVE

Infantile epileptic spasm syndrome (IESS), including West syndrome (WS) and infantile spasm (IS), causes a challenging prognosis, particularly when associated with metabolic etiologies.

METHODS

This study, conducted at a tertiary pediatric neurology center, explored the prevalence and clinical features of inborn errors of metabolism in 112 children with IESS over 10 years.

RESULTS

Most patients presented with seizures, primarily flexor spasms, and the median age at onset was 5 months. Comprehensive clinical evaluation and neuroimaging revealed structural-acquired causes as the most common etiology. Notably, inborn errors of metabolism were identified in 5.4 % of cases, with six distinct diagnoses including nonketotic hyperglycinemia, pyridoxine-dependent epilepsy, primary coenzyme Q10 deficiency 7, congenital disorder of glycosylation type IIM, 6-pyruvoyl tetrahydrobiopterin synthase deficiency, and argininosuccinate lyase deficiency. The prevalence of inborn errors of metabolism in this cohort was consistent with global variations reported in the literature. Genetic testing, including karyotype analysis and whole exome sequencing, was performed in a subset of cases with no clear diagnosis, revealing abnormalities in approximately 50 % of cases. Adrenocorticotropic hormone emerged as the most frequently prescribed antiseizure medication.

CONCLUSION

This study provides insight into the diagnostic challenges associated with IESS and highlights the importance of metabolic investigations, especially in cases without a clear etiology. The findings emphasize the need for further genetic and metabolic studies to enhance prognostic accuracy and guide potential treatment options for children with IESS, particularly in populations with high rates of consanguinity.

Ethnically unique disease burden and limitations of current expanded carrier screening panels

OBJECTIVES

The purpose of the study is to identify the recessive diseases currently affecting real-world pediatric patients in Taiwan, and whether current extended carrier screening panels have the coverage and detective power to identify the pathogenic variants in the carrier parents.

METHODS

A total of 132 trio-samples were collected from May 2017 to March 2022. The participants were parents of pediatric intensive care unit patients who were critically ill or infants with abnormal newborn screening results. A retrospective carrier screening scheme was applied to analyze only the carrier status of pathogenic or likely pathogenic recessive variants resulting in diseases in their children. The recessive disorders diagnosed in our cohort were compared with the gene content in commercial panels.

RESULTS

Mutations in COQ4, PEX1, OTC, and IKBKG were the most frequently identified. In the parents of 44 children with confirmed diagnoses of recessive diseases, 47 (53.40%) screened positive for being the carriers of the same recessive disorders diagnosed in their children. The commercial panels covered 35.13% to 54.05% of the disorders diagnosed in this cohort.

CONCLUSION

Clinicians and genetic counselors should be aware of the limitations of current extended carrier screening and interpret negative screening results with caution. Future panels should also consider genes with ethnically unique mutations such as pathogenic variants of the COQ4 gene in the East Asian population.