[Clinical and genetic analysis of a patient with Loeys-Dietz syndrome due to variant of TGFBR2 gene].

Objective: To explore the genetic basis of a patient with clinically suspected Loeys-Dietz syndrome (LDS).
Methods: A child who had presented at Beijing Anzhen Hospital in September 2018 was selected as the study subject. Clinical data and family history of the patient were collected, along with peripheral blood samples of the proband and his parents. Whole exome sequencing (WES) was carried out through next-generation sequencing.
Results: Candidate variants were searched through bioinformatic analysis focusing on genes associated with hereditary aortic aneurysms. Candidate variant was verified by Sanger sequencing. The patient was found to have cardiovascular abnormalities including early-onset aortic dilatation and coarctation, and LDS syndrome was suspected. WES revealed that he has harbored a heterozygous c.1526G>T missense variant of the TGFBR2 gene. The same variant was not found in either parent and was predicted as likely pathogenic (PM1+PM2_Supporting+ PM6+PP3+PP4) based on the guidelines from the American College for Medical Genetics and Genomics (ACMG).
Conclusion: The TGFBR2 c.1526G>T variant probably underlay the LDS in this patient and was unreported previously in China. Above finding has enriched the mutational spectrum of the TGFBR2 gene associated with the LDS and provided a basis for the genetic counseling for the patient.