Multilocus disease-causing genomic variations for Mendelian disorders: role of systematic phenotyping and implications on genetic counselling

Dhanya Lakshmi Narayanan, Divya Udyawar, Parneet Kaur, Suvasini Sharma, Narayanaswamy Suresh, Sheela Nampoothiri, Michelle C. do Rosario, Puneeth H. Somashekar, Lakshmi Priya Rao, Neethukrishna Kausthubham, Purvi Majethia, Shruti Pande, Y. Ramesh Bhat, Aroor Shrikiran, Stephanie Bielas, Katta Mohan Girisha, Anju Shukla

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Multilocus disease-causing genomic variations (MGVs) and multiple genetic diagnoses (MGDs) are increasingly being recognised in individuals and families with Mendelian disorders. This can be mainly attributed to the widespread use of genomic tests for the evaluation of these disorders. We conducted a retrospective study of families evaluated over the last 6 years at our centre to identify families with MGVs and MGDs. MGVs were observed in fourteen families. We observed five different consequences: (i) individuals with MGVs presenting as blended phenotypes (ii) individuals with MGVs presenting with distinct phenotypes (iii) individuals with MGVs with age-dependent penetrance (iv) individuals with MGVs with one phenotype obscured by another more predominant phenotype (v) two distinct phenotypes in different individuals in families with MGVs. Consanguinity was present in eight (8/14, 57.1%) of them. Thirteen families had two Mendelian disorders and one had three Mendelian disorders. The risk of recurrence of one or more conditions in these families ranged from 25% to 75%. Our findings underline the importance of the role of a clinical geneticist in systematic phenotyping, challenges in genetic counselling and risk estimation in families with MGVs and MGDs, especially in highly inbred populations.

Original languageEnglish
JournalEuropean Journal of Human Genetics
DOIs
Publication statusAccepted/In press - 2021

All Science Journal Classification (ASJC) codes

  • Genetics
  • Genetics(clinical)

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