Genotype–phenotype correlations in recessive titinopathies
Genetics in Medicine, 2020•nature.com
Purpose High throughput sequencing analysis has facilitated the rapid analysis of the entire
titin (TTN) coding sequence. This has resulted in the identification of a growing number of
recessive titinopathy patients. The aim of this study was to (1) characterize the causative
genetic variants and clinical features of the largest cohort of recessive titinopathy patients
reported to date and (2) to evaluate genotype–phenotype correlations in this cohort.
Methods We analyzed clinical and genetic data in a cohort of patients with biallelic …
titin (TTN) coding sequence. This has resulted in the identification of a growing number of
recessive titinopathy patients. The aim of this study was to (1) characterize the causative
genetic variants and clinical features of the largest cohort of recessive titinopathy patients
reported to date and (2) to evaluate genotype–phenotype correlations in this cohort.
Methods We analyzed clinical and genetic data in a cohort of patients with biallelic …
Purpose
High throughput sequencing analysis has facilitated the rapid analysis of the entire titin (TTN) coding sequence. This has resulted in the identification of a growing number of recessive titinopathy patients. The aim of this study was to (1) characterize the causative genetic variants and clinical features of the largest cohort of recessive titinopathy patients reported to date and (2) to evaluate genotype–phenotype correlations in this cohort.
Methods
We analyzed clinical and genetic data in a cohort of patients with biallelic pathogenic or likely pathogenic TTN variants. The cohort included both previously reported cases (100 patients from 81 unrelated families) and unreported cases (23 patients from 20 unrelated families).
Results
Overall, 132 causative variants were identified in cohort members. More than half of the cases had hypotonia at birth or muscle weakness and a delayed motor development within the first 12 months of life (congenital myopathy) with causative variants located along the entire gene. The remaining patients had a distal or proximal phenotype and a childhood or later (noncongenital) onset. All noncongenital cases had at least one pathogenic variant in one of the final three TTN exons (362–364).
Conclusion
Our findings suggest a novel association between the location of nonsense variants and the clinical severity of the disease.
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