Genetic Counseling and NGS Screening for Recessive LGMD2A Families

Area of Science:

• Genetics
• Neurology
• Medical Diagnostics

Background:

• Limb-girdle muscular dystrophies (LGMDs) present significant diagnostic challenges due to clinical and genetic heterogeneity.
• Accurate genetic counseling is essential for determining appropriate molecular assays and estimating recurrence risks.

Purpose of the Study:

• To illustrate a comprehensive genetic counseling approach for families with a history of recessive LGMD, specifically LGMD2A.
• To emphasize the importance of assessing the genetic background of phenotypically unaffected partners.

Main Methods:

• Segregation analysis of known CAPN3 mutations within the affected family.
• Next-generation sequencing (NGS) in phenotypically unaffected partners to identify carrier status.
• Integrated genetic analysis combining family history and partner sequencing for risk assessment.

Main Results:

• A family with LGMD2A (calpainopathy) exhibiting compound heterozygosity for two CAPN3 mutations was analyzed.
• Segregation analysis confirmed mutation inheritance patterns within the family.
• NGS on unaffected partners provided a detailed genetic background, enabling precise reproductive risk estimation.

Conclusions:

• Genetic counseling for LGMDs, particularly recessive types, necessitates evaluating the genetic status of both partners in a couple.
• Testing unaffected partners is vital for accurate recurrence risk assessment and reproductive decision-making.
• This comprehensive approach supports genetic counselors in offering tailored strategies, including prenatal testing and medical surveillance.