Test Change Memorandum

Effective January 3, 2014, the Medical Genetics Laboratories at Baylor College of Medicine will supplant Test Code 3500 – Mitochondrial/Metabolic (MitoMet®) Microarray Analysis with Test Code 2000 – Mitochondrial/Metabolic (MitoMet®Plus) Microarray Analysis, which offers more extensive coverage.

Most nuclear genes on the MitoMet®Plus Microarray have exon by exon coverage and the MitoMet®Plus Microarray Analysis covers more genes than its predecessor. This array contains 180,000 oligonucleotide probes targeted to both mitochondrial and nuclear genes involved in mitochondrial and metabolic related diseases. Approximately, 3,200 probes cover the entire 16.6 kb mitochondrial genome. In addition, oligo probes targeted to close to 1,600 nuclear genes that are involved in mtDNA biogenesis, maintenance of mitochondrial deoxynucleotide pools, mitochondrial transcription and translation factors, respiratory chain complex assembly and complex subunits, urea cycle disorders, fatty acid oxidation, amino acid metabolism, creatine pathway, progressive familial intrahepatic cholestasis, retinitis pigmentosa, high/low bone mass, plus many more, are in the array.

This analysis will not detect balanced genomic rearrangements, point mutations or small deletion/duplication mutations. Large mtDNA deletion heteroplasmy of less than 15% may not be detected. Nuclear gene deletions less than 1 kb and mtDNA deletions less than 200 bp may not be detected. This array has detected deletions/duplications as small as 200 bp in the nuclear genome.

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