Identification and characterization of 30 novel pathogenic variations in 69 unrelated Indian patients with Mucolipidosis Type II and Type III

Divya Pasumarthi, Neerja Gupta, Jayesh Sheth, S. Jamal Md Nurul Jain, Ikrormi Rungsung, Madhulika Kabra, Prajnya Ranganath, Shagun Aggarwal, Shubha R. Phadke, Katta M. Girisha, Anju Shukla, Chaitanya Datar, Ishwar C. Verma, Ratna Dua Puri, Riddhi Bhavsar, Mehul Mistry, V. H. Sankar, Kalpana Gowrishankar, Divya Agrawal, Mohandas NairSumita Danda, Jai Prakash Soni, Ashwin Dalal

Research output: Contribution to journalArticlepeer-review

Abstract

Mucolipidosis (ML) (OMIM 607840 & 607838) is a rare autosomal recessive inherited disorder that occurs due to the deficiency of golgi enzyme uridine diphosphate (UDP)– N-acetylglucosamine-1-phosphotransferase (GlcNAc-phosphotransferase) responsible for tagging mannose-6-phosphate for proper trafficking of lysosomal enzymes to lysosomes. Variants in GlcNAc-phosphotransferase (GNPTAB (α, β subunits) and GNPTG (γ subunits) are known to result in impaired targeting of lysosomal enzymes leading to Mucolipidosis (ML) Type II or Type III. We analyzed 69 Indian families of MLII/III for clinical features and molecular spectrum and performed in silico analysis for novel variants. We identified 38 pathogenic variants in GNPTAB and 5 pathogenic variants in GNPTG genes including missense, frame shift, deletion, duplication and splice site variations. A total of 26 novel variants were identified in GNPTAB and 4 in GNPTG gene. In silico studies using mutation prediction software like SIFT, Polyphen2 and protein structure analysis further confirmed the pathogenic nature of the novel sequence variants detected in our study. Except for a common variant c.3503_3504delTC in early onset MLII, we could not establish any other significant genotype and phenotype correlation. This is one of the largest studies reported till date on Mucolipidosis II/III in order to identify mutation spectrum and any recurrent mutations specific to the Indian ethnic population. The mutational spectrum information in Indian patients will be useful in better genetic counselling, carrier detection and prenatal diagnosis for patients with ML II/III.

Original languageEnglish
JournalJournal of Human Genetics
DOIs
Publication statusAccepted/In press - 2020

All Science Journal Classification (ASJC) codes

  • Genetics
  • Genetics(clinical)

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