The second-tier status of fragile X syndrome testing for unexplained intellectual disability/global developmental delay in the era of next-generation sequencing

• Main Authors: Wen Zhang (Author), Dong Li (Author), Nan Pang (Author), Li Jiang (Author), Baomin Li (Author), Fanghua Ye (Author), Fang He (Author), Shimeng Chen (Author), Fangyun Liu (Author), Jing Peng (Author), Jinghua Yin (Author), Fei Yin (Author)
• Format: Book
• Published: Frontiers Media S.A., 2022-07-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

ObjectiveAlthough many unexplained intellectual disability/global developmental delay (ID/GDD) individuals have benefited from the excellent detection yield of copy number variations and next-generation sequencing testing, many individuals still who suffer from ID/GDD of unexplained etiology. In this study, we investigated the applicability of fragile X syndrome (FXS) testing in unexplained ID/GDD individuals with negative or absent genetic testing.MethodsIn this study, we used the triplet repeat primed polymerase chain reaction to evaluate the value and application of fragile X testing in unexplained ID/GDD individuals with negative or absent genetic testing (n = 681) from three hospitals.ResultsOf the 681 ID/GDD individuals with negative or absent genetic testing results detected by FXS testing, 12 men and one woman were positive. This corresponded to a diagnostic yield of 1.9% for FXS testing in our cohort. All FXS individuals had either a family history of ID/GDD or suggestive clinical features. The detection yield of FXS testing in ID/GDD individuals who completed genetic testing (2.70%, 12/438) was significantly higher than in individuals without any genetic testing (0.40%, 1/243).ConclusionsThis is the first report of FXS testing in ID/GDD individuals who lacked previous genetic testing, which promotes standardization of the FXS diagnostic process. These results highlight the utility of FXS testing of unexplained ID/GDD individuals with negative results from standard genetic testing. In the era of next-generation sequencing, FXS testing is more suitable as a second-tier choice and provides clinicians and geneticists with auxiliary references for tracing the etiology of ID/GDD.

Item Description

2296-2360
10.3389/fped.2022.911805