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Posts Tagged ‘NIH Undiagnosed Diseases Network’

Two brothers with MEPAN Syndrome: A Rare Genetic Disorder

Reporter: Amandeep Kaur

In the early 40s, a married couple named Danny and Nikki, had normal pregnancy and delivered their first child in October 2011.  The couple was elated after the birth of Carson because they were uncertain about even conceiving a baby. Soon after birth, the parents started facing difficulty in feeding the newborn and had some wakeful nights, which they used to called “witching hours”. For initial six months, they were clueless that something was not correct with their infant. Shortly, they found issues in moving ability, sitting, and crawling with Carson. Their next half year went in visiting several behavioral specialists and pediatricians with no conclusion other than a suggestion that there is nothing to panic as children grow at different rates.

Later in early 2013, Caron was detected with cerebral palsy in a local regional center. The diagnosis was based on his disability to talk and delay in motor development. At the same time, Carson had his first MRI which showed no negative results. The parents convinced themselves that their child condition would be solved by therapies and thus started physical and occupational therapies. After two years, the couple gave birth to another boy child named Chase in 2013. Initially, there was nothing wrong with Chase as well. But after nine months, Chase was found to possess the same symptoms of delaying in motor development as his elder brother. It was expected that Chase may also be suffering from cerebral palsy. For around one year both boys went through enormous diagnostic tests starting from karyotyping, metabolic screen tests to diagnostic tests for Fragile X syndrome, lysosomal storage disorders, Friedreich ataxia and spinocerebellar ataxia. Gene panel tests for mitochondrial DNA and Oxidative phosphorylation (OXPHOS) deficiencies were also performed. No conclusion was drawn because each diagnostic test showed the negative results.

Over the years, the condition of boys was deteriorating as their movements became stiffer and ataxic, they were not able to crawl anymore. By the end of 2015, the boys had an MRI which showed some symmetric anomalies in their basal ganglia indicating a metabolic condition. The symptoms of Carson and Chase was not even explained by whole exome sequencing due to the absence of any positive result. The grievous journey of visits to neurologist, diagnostic tests and inconclusive results led the parents to rethink about anything happened erroneous due to them such as due to their lifestyle, insufficient intake of vitamins during pregnancy or exposure to toxic agents which left their sons in that situation.

During the diagnostic odyssey, Danny spent many restless and sleepless nights in searching PubMed for any recent cases with symptoms similar to his sons and eventually came across the NIH’s Undiagnosed Diseases Network (UDN), which gave a light of hope to the demoralized family. As soon as Danny discovered about the NIH’s Diseases Network, he gathered all the medical documents of both his sons and submitted the application. The submitted application in late 2015 got accepted a year later in December 2016 and they got their first appointment in early 2017 at the UDN site at Stanford. At Stanford, the boys had gone through whole-genome sequencing and some series of examinations which came back with inconclusive results. Finally, in February 2018, the family received some conclusive results which explained that the two boys suffer from MEPAN syndrome with pathogenic mutations in MECR gene.

  • MEPAN means Mitochondrial Enoyl CoA reductase Protein-Associated Neurodegeneration
  • MEPAN syndrome is a rare genetic neurological disorder
  • MEPAN syndrome is associated with symptoms of ataxia, optic atrophy and dystonia
  • The wild-type MECR gene encodes a mitochondrial protein which is involved in metabolic processes
  • The prevalence rate of MEPAN syndrome is 1 in 1 million
  • Currently, there are 17 patients of MEPAN syndrome worldwide

The symptoms of Carson and Chase of an early onset of motor development with no appropriate biomarkers and T-2 hyperintensity in the basal ganglia were matching with the seven known MEPAN patient at that time. The agonizing journey of five years concluded with diagnosis of rare genetic disorder.

Despite the advances in genetic testing and their low-cost, there are many families which still suffer and left undiagnostic for long years. To shorten the diagnostic journey of undiagnosed patients, the whole-exome and whole-genome sequencing can be used as a primary tool. There is need of more research to find appropriate treatments of genetic disorders and therapies to reduce the suffering of the patients and families. It is necessary to fill the gap between the researchers and clinicians to stimulate the development in diagnosis, treatment and drug development for rare genetic disorders.

The family started a foundation named “MEPAN Foundation” (https://www.mepan. org) to reach out to the world to educate people about the mutation in MECR gene. By creating awareness among the communities, clinicians, and researchers worldwide, the patients having rare genetic disorder can come closer and share their information to improve their condition and quality of life.

Reference: Danny Miller, The diagnostic odyssey: our family’s story, The American Journal of Human Genetics, Volume 108, Issue 2, 2021, Pages 217-218, ISSN 0002-9297, https://doi.org/10.1016/j.ajhg.2021.01.003 (https://www.sciencedirect.com/science/article/pii/S0002929721000033)

Sources:

https://www.variantyx.com/2020/02/26/in-silico-panel-expansion/

https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=508093

https://www.mepan. org

Other related articles were published in this Open Access Online Scientific Journal, including the following:

Effect of mitochondrial stress on epigenetic modifiers

Larry H. Bernstein, MD, FCAP, Curator, LPBI

https://pharmaceuticalintelligence.com/2016/05/07/effect-of-mitochondrial-stress-on-epigenetic-modifiers/

The Three Parent Technique to Avoid Mitochondrial Disease in Embryo

Reporter and Curator: Dr. Sudipta Saha, Ph.D.

https://pharmaceuticalintelligence.com/2016/10/07/the-three-parent-technique-to-avoid-mitochondrial-disease-in-embryo/

New Insights into mtDNA, mitochondrial proteins, aging, and metabolic control

Larry H. Bernstein, MD, FCAP, Curator, LPBI

https://pharmaceuticalintelligence.com/2016/04/20/new-insights-into-mtdna-mitochondrial-proteins-aging-and-metabolic-control/

Mitochondrial Isocitrate Dehydrogenase and Variants

Writer and Curator: Larry H. Bernstein, MD, FCAP

https://pharmaceuticalintelligence.com/2015/04/02/mitochondrial-isocitrate-dehydrogenase-and-variants/

Update on mitochondrial function, respiration, and associated disorders

Larry H. Benstein, MD, FCAP, Gurator and writer

https://pharmaceuticalintelligence.com/2014/07/08/update-on-mitochondrial-function-respiration-and-associated-disorders/

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