The hypothesis of this FDA-IRB approved open-label pilot trial was that patients with ASD and mt dysfunction would improve clinically and/or biochemically following treatment with a combination of carnitine, coenzyme Q10 and alpha-lipoic acid (MitoCocktail).
Objective: We report two patients with novel mutations in SPATA5 who demonstrate biochemical evidence of mitochondrial dysfunction. Background: Mutations in SPATA5 gene are associated with “Epilepsy, Hearing Loss and Mental Retardation Syndrome” (EHLMRS). There is recent experimental evidence from animal models that the SPATA5 gene is involved in mitochondrial remodeling, ATP production and brain development. Design/Methods: Both patients presented with seizures, sensorineural hearing loss, global developmental delays, and hypotonia. Patient 1 and 2 underwent extensive biochemical workup and neuroimaging. Patient 2 had a chromosome microarray which showed a 51 kb loss of 4q28.1, which involved a portion of the SPATA5 gene – at the time, thought to be benign. Both Patient 1 and Patient 2 underwent testing for mitochondrial dysfunction using buccal swab analysis for three enzymes: citrate synthase to to evaluate overall mitochondrial content, and Complex I and IV activity levels. Finally, both patients underwent Whole Exome Sequencing. Results: Patient 1 revealed normal citrate synthase levels, normal Complex I and low Complex IV levels. Patient 2 buccal swab testing revealed very high citrate synthase levels, with low Complex I and IV. Patient 1 had two compound heterozygous mutations in the SPATA5 gene: p.G357X (c.1069 G>T in exon 5) and p.P102S (c.304 C>T in exon 3). Patient 2 had a maternally inherited deletion of Exons 12–13, as well as a “variant of uncertain significance” p.Lys638Glu (c.1912 A>G in exon 11) in the SPATA5 gene. Conclusions: Our patients’ novel mutations and unusual phenotypes demonstrate that SPATA5 deficiency leads to altered mitochondria respiratory function, supporting experimental evidence that it delays development of cortical neurons. We suggest that SPATA5 mutations be considered in the work up of a patient with presumptive mitochondrial encephalopathy. Disclosure: Dr. Khurana has nothing to disclose. Dr. Weaver has nothing to disclose. Dr. Miskin has nothing to disclose. Dr. Melvin has nothing to disclose. Dr. Goldenthal has nothing to disclose.
Aim: Mitochondrial function studies in autism spectrum disorders (ASD) have detected skeletal muscle mitochondrial enzyme deficiencies in respiratory complex (RC) activities. As a muscle biopsy is expensive and invasive, we assessed RC-I and RC-IV activities in buccal swabs. Methods: 92 children with ASD and 68 controls were studied with immunocapture for RC-I and microspectrophotometry for RC-IV. Results: Significant RC activity deficiencies were found in 39 (42%) ASD patients (p < 0.01) and more prevalent in more severe cases. Aberrant RC overactivity was seen in 9 children. RC-I/RC-IV activity ratio was significantly increased in 64% of the entire ASD cohort including 76% of those more severely affected (p < 0.05). Conclusion: Buccal swab analysis revealed extensive RC abnormalities in ASD providing a noninvasive biomarker to assess mitochondrial function in ASD patients.
The extent of intra- and inter-specific variation in mitochondrial DNA and nuclear ribosomal RNA gene restriction sites was determined for the four sibling species of the Anopheles quadrimaculatus complex. Individual mosquitoes were identified by allozyme analysis according to previously published keys, and the total genomic DNA of these same individuals was then cleaved with restriction enzymes. Restriction maps of mitochondrial DNA, including the positions of variable sites, were constructed for each species. No evidence for interspecific hybridization was found in the populations surveyed. There was little variation in restriction patterns within any given species, but differences occurred among the four. Three restriction enzymes (AvaI, HindIII, and PvuII) yielded species-specific DNA restriction patterns for the mitochondrial DNA, while AvaI and HindIII produced diagnostic patterns for the ribosomal DNA. Thus, restriction patterns were very useful for detecting cryptic species but less appropriate than isozymes for studying genetic structure of populations within species.
Autism spectrum disorder (ASD) has been associated with mitochondrial dysfunction but few studies have examined the relationship between mitochondrial function and ASD symptoms. We measured Complex I and IV and citrate synthase activities in 76 children with ASD who were not receiving vitamin supplementation or medication. We also measured language using the Preschool Language Scales or Clinical Evaluation of Language Fundamentals, adaptive behavior using the Vineland Adaptive Behavioral Scale, social function using the Social Responsiveness Scale and behavior using Aberrant Behavior Checklist, Childhood Behavior Checklist and the Ohio Autism Clinical Impression Scale. Children with ASD demonstrated significantly greater variation in mitochondrial activity compared to controls with more than expected ASD children having enzyme activity outside of the normal range for Citrate Synthase (24%), Complex I (39%) and Complex IV (11%). Poorer adaptive skills were associated with Complex IV activity lower or higher than average and lower Complex I activity. Poorer social function and behavior was associated with relatively higher Citrate Synthase activity. Similar to previous studies we find both mitochondrial underactivity and overactivity in ASD. This study confirms an expanded variation in mitochondrial activity in ASD and demonstrates, for the first time, that such variations are related to ASD symptoms.
The authors describe mitochondrial studies in a 6-year-old patient with a seizure disorder that can be seen in myoclonic epilepsy and ragged red fibers. Using a recently developed noninvasive approach, analysis of buccal mitochondrial enzyme function revealed severe respiratory complex I and IV deficiencies in the patient. In addition, analysis of buccal mitochondrial DNA showed significant amounts of the common 5 kb and 7.4 kb mitochondrial DNA deletions, also detectable in blood. This study suggests that a buccal swab approach can be used to informatively examine mitochondrial dysfunction in children with seizures and may be applicable to screening mitochondrial disease with other clinical presentations.
Cardiomyopathy and neuromuscular abnormalities may simultaneously coexist and present with defects in mitochondrial DNA and bioenergetic function. We sought to evaluate the relationship between clinical and mitochondrial phenotypes in 28 young patients with both cardiomyopathy and neurologic disorders including seizures, dystonia, ophthalmoplegia, Kearns-Sayre syndrome, Leigh disease, and Friedreich's ataxia. All tissues examined displayed marked defects in respiratory complex activities. Five patients had abundant large-scale mitochondrial DNA deletions and one patient displayed a pathogenic point mutation previously reported with mitochondrial cytopathy. In this cohort, patients with hypertrophic cardiomyopathy displayed a higher incidence of complex I defects, fewer DNA deletions and mitochondrial structural abnormalities and were less often associated with developmental delay phenotype compared with patients with dilated cardiomyopathy. Although structural abnormalities are present in a subset of patients, evaluation of respiratory enzyme activity appears to be most informative whether tissues examined were derived from heart or skeletal muscle. Defects in mitochondrial DNA and bioenergetics are frequently present in children with cardiomyopathy presenting with a variety of neurologic abnormalities and are amenable to biochemical and molecular analysis.
