Thumb duplication: molecular analysis of different clinical types
Molecular analysis of different types of thumb duplication and identification of new suspected gene mutations.
Materials and methods
In a series of patients operated for polydactyly, DNA was extracted from blood samples collected preoperatively. Among these, the samples of two patients with thumb duplication (Wassel types III and IV) were initially selected for molecular analysis. The method of Clinical Exome Solution was used for the study of the phenotype-involved genes. Next-generation sequencing (NGS) was performed on a NextSeq-500 Platform (Illumina), and Sophia DDM® SaaS algorithms were used for the bioinformatics analysis of the data.
In total, 8—including 4 new—mutations were detected in CEP290 (1 mutation), RPGRIP1 (2 mutations), TMEM216 (2 mutations), FBN1 (1 mutation), CEP164 (1 mutation), and MEGF8 (1 mutation) genes. NGS revealed 3 mutated genes in the patient with Wassel III thumb duplication and 5 mutated genes in the patient with Wassel IV duplication. The molecular analysis revealed that the patients had 2 mutated genes in common, but they only shared one common mutation.
The new detected mutations are most probably associated with thumb duplication, as they belong to genes with already described mutations causing ciliopathies, often including polydactyly in their phenotype. Recognition of these mutations will be helpful to prenatal diagnosis, operative treatment strategy prediction, and possible future experimental applications in gene therapy.
KeywordsPolydactyly Thumb duplication Gene Mutation Next-generation sequencing Ciliopathy
Compliance with ethical standards
Conflict of interest
All authors declare that they have no conflict of interest.
This study was approved by the institutional review board and follows the ethical principles for medical research involving human subjects of the World Medical Association Declaration of Helsinki.
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