Clinical and molecular characterization of a patient with mitochondrial Neurogastrointestinal Encephalomyopathy

Parham Habibzadeh, Mohammad Silawi, Hassan Dastsooz, Shima Bahramjahan, Shahrokh Ezzatzadegan Jahromi, Vahid Reza Ostovan, Majid Yavarian, Mohammad Mofatteh, Mohammad Ali Faghihi

Research output: Contribution to journalArticle

Abstract

Background: Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is a rare autosomal recessive disorder caused by mutations in TYMP gene, encoding nuclear thymidine phosphorylase (TP). MNGIE mainly presents with gastrointestinal symptoms and is mostly misdiagnosed in many patients as malabsorption syndrome, inflammatory bowel disease, anorexia nervosa, and intestinal pseudo-obstruction. Up to date, more than 80 pathogenic and likely pathogenic mutations associated with the disease have been reported in patients from a wide range of ethnicities. The objective of this study was to investigate the underlying genetic abnormalities in a 25-year-old woman affected with MNGIE. Case presentation: The patient was a 25-year-old female referred to our center with the chief complaint of severe abdominal pain and diarrhea for 2 years that had worsened from 2 months prior to admission. The clinical and para-clinical findings were in favor of mitochondrial neurogastrointestinal encephalomyopathy syndrome. Subsequent genetic studies revealed a novel, private, homozygous nonsense mutation in TYMP gene (c. 1013 C > A, p.S338X). Sanger sequencing confirmed the new mutation in the proband. Multiple sequence alignment showed high conservation of amino acids of this protein across different species. Conclusion: The detected new nonsense mutation in the TYMP gene would be very important for genetic counseling and subsequent early diagnosis and initiation of proper therapy. This novel pathogenic variant would help us establish future genotype-phenotype correlations and identify different pathways related to this disorder.

Original languageEnglish (US)
Article number142
JournalBMC Gastroenterology
Volume20
Issue number1
DOIs
StatePublished - May 8 2020

Keywords

  • Codon, nonsense
  • Mitochondrial diseases
  • Mitochondrial neurogastrointestinal encephalomyopathy syndrome
  • TYMP

ASJC Scopus subject areas

  • Gastroenterology

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    Habibzadeh, P., Silawi, M., Dastsooz, H., Bahramjahan, S., Ezzatzadegan Jahromi, S., Ostovan, V. R., Yavarian, M., Mofatteh, M., & Faghihi, M. A. (2020). Clinical and molecular characterization of a patient with mitochondrial Neurogastrointestinal Encephalomyopathy. BMC Gastroenterology, 20(1), [142]. https://doi.org/10.1186/s12876-020-01280-5