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Mitochondrial DNA haplogroup 'R' is associated with Noonan syndrome of south India

Deepa Selvi Rani1, Perundurai S Dhandapany, Pratibha Nallari

  • 1Centre for Cellular and Molecular Biology (CSIR), Hyderabad, India.

Mitochondrion
|December 17, 2009
PubMed

Insights

Noonan syndrome (NS) is often linked to PTPN11 gene mutations. This study found no PTPN11 mutations but identified novel mitochondrial DNA mutations and exclusive haplogroups in South Indian NS patients, suggesting a potential role in the disease.

Area of Science:

  • Genetics
  • Mitochondrial DNA research
  • Human population genetics

Background:

  • Noonan syndrome (NS) is a genetic disorder.
  • Mutations in the PTPN11 gene are found in about 50% of NS cases.
  • The genetic basis for NS in some patients remains unexplained.

Purpose of the Study:

  • To investigate the genetic causes of Noonan syndrome (NS) in South Indian patients.
  • To explore the role of mitochondrial DNA (mtDNA) and specific haplogroups in NS.
  • To identify novel genetic variants associated with NS.

Main Methods:

  • Analysis of PTPN11 gene mutations in seven NS patients.
  • Complete mitochondrial DNA (mtDNA) sequencing for all patients.
  • Haplogroup analysis to determine maternal lineage and population clustering.

Main Results:

  • No PTPN11 gene mutations were detected in the studied NS patients.
  • 146 mtDNA mutations were identified, including five novel mutations, one of which was heteroplasmic and non-synonymous (A11144R).
  • All seven NS probands and their maternal relatives belonged to haplogroup R and its novel sub-haplogroups (R7b1b, R30a1, R30c, T2b7, U9a1), which were exclusive to the NS cohort.

Conclusions:

  • The PTPN11 gene is not the sole cause of Noonan syndrome (NS) in this South Indian cohort.
  • Novel mtDNA mutations and specific haplogroups within haplogroup R may play a significant role in the pathogenesis of NS in South Indian populations.
  • Further research into these mtDNA variations and haplogroups is warranted to understand their influence on NS development.

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