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[Genetic analysis of a child with XYY syndrome mainly featuring mental retardation]
Yi Liu1, Rui Dong, Kaihui Zhang
1Pediatric Research Institute, Institute of Pediatric Health Care, Qilu Children's Hospital of Shandong University, Jinan, Shandong 250022, China.
Objective:
To explore the genetic cause for a boy featuring mainly with mental retardation.
Methods:
G-banding karyotyping and fluorescence in situ hybridization (FISH) were carried out for the child and his parents. The child was also analyzed with chromosome microarray (CMA). Suspected microdeletion was validated with quantitative PCR.
Results:
The proband was found to have a 47,XYY karyotype by both chromosome and FISH analyses, while both of his parents had a normal karyotype. CMA suggested that the proband had one copy of X chromosome and two copies of Y chromosome. In addition, CMA has also detected deletion of the KYNU gene (mapped at 2q22.2), which could be pathogenic. The result was confirmed by qPCR.
Conclusion:
For its high resolution, CMA can be used to identify potential microdeletion/duplications among children with chromosome aneuploidy and unusual phenotypes.
Related Concept Videos
01:35Pedigree Analysis
01:43Sex-linked Disorders
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01:17Karyotyping
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The germline cells such as egg and sperm cells carry only half the number of chromosomes, i.e., 22 autosomes and one sex chromosome. All eggs have an X chromosome, while sperm cells can carry an X or...
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Evolution
Around 300 million years ago, the two sex chromosomes diverged from two identical autosomal chromosomes. Over time, the Y chromosome has lost most of its genes, shrinking in size....