| Interpretive Data: |
Background Information for: X Chromosome Ultra-High Density Microarray, 954 Genes:
Characteristics: X-linked genetic defects are responsible for up to 30 percent of inherited intellectual disabilities (ID). Additionally, many well-described disorders not involving ID have been mapped to the X chromosome. These disorders fall into several general categories such as hearing loss, hemophilias, immunodeficiency disorders, metabolic disorders, myopathies, neuromuscular disorders, and skin disorders.
Incidence: Varies by disorder.
Inheritance: X-linked recessive and X-linked dominant.
Penetrance: Variable depending on gene(s) involved and gender.
Cause: Pathogenic copy number change involving one or more genes on the X chromosome.
Clinical Sensitivity: Unknown.
Methodology: This comparative genomic hybridization array uses 720,000 custom designed probes, providing very dense coverage of all 954 identified genes located on the X chromosome. At the exonic level, probes are tiled at 15 base pair (bp) intervals, providing contiguous coverage of each exon of each gene. Within intronic and flanking regions of each gene, probes are spaced 135 bp apart. Across the intergenic regions of the chromosome, probes are spaced 525 bp (0.5 kb) apart. Copy number changes are calculated based on hybridization signal ratios between the patient and control samples.
Analytical Sensitivity: 99 percent with a 95 percent confidence interval of 81.5-100 percent.
Limitations: This technique will only detect copy number imbalances within the X chromosome. Balanced rearrangements, base pair changes, or numerical X chromosome changes, such as Klinefelter, Turner or triple X syndromes, will not be detected. Copy number imbalances for areas of high sequence similarity may not be detected. Genomic imbalances smaller than the resolution of this array, regions of the genome not represented on the array, and mosaicism will not be detected. A negative result does not exclude the diagnosis of any of the disorders represented on the microarray.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.
Refer to Statement C under Testing Information at http://www.aruplab.com.
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| CPT Code(s): |
83891 Isolation; 88386 x4 Array-based evaluation of multiple molecular probes, 251-500
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Cross References: |
CGH X Chromosome (X Chromosome Ultra-High Density Microarray, 954 Genes), GMA X Chromosome (X Chromosome Ultra-High Density Microarray, 954 Genes), ID (X Chromosome Ultra-High Density Microarray, 954 Genes), Intellectual Disability (X Chromosome Ultra-High Density Microarray, 954 Genes), Mental Retardation (X Chromosome Ultra-High Density Microarray, 954 Genes), Microarray X Chromosome (X Chromosome Ultra-High Density Microarray, 954 Genes), MR (X Chromosome Ultra-High Density Microarray, 954 Genes), X-Linked Mental Retardation (X Chromosome Ultra-High Density Microarray, 954 Genes), XLMR (X Chromosome Ultra-High Density Microarray, 954 Genes) |
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