Associated disorders

The PCBD1 gene is associated with tetrahydrobiopterin-deficient hyperphenylalaninemia due to pterin-4-α-carbinolamine dehydratase deficiency (MedGen UID: 440773).

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Invitae tests that include this gene:

An estimated 1-3% of hyperphenylalaninemia cases are due to defects in tetrahydrobiopterin metabolism. Of the 1-3% of cases, approximately 5% of them are due to pterin-4-α-carbinolamine dehydratase deficiency.

Tetrahydrobiopterin (BH4) functions as a cofactor to phenylalanine hydroxylase by donating electrons during the catabolism of phenylalanine to tyrosine. BH4 is recycled after each use and must be regenerated from the oxidized state. The PCBD1 gene encodes the enzyme pterin-4-α-carbinolamine dehydratase (PCD); which catalyzes the dehydration of 4α-hydroxy-tetrahydrobiopterin (oxidized state of BH4) to quinonoid dihydrobiopterin. This is the first of the two steps in the BH4 salvage pathway.

Assay and technical information

Invitae is a College of American Pathologists (CAP)-accredited and Clinical Laboratory Improvement Amendments (CLIA)-certified clinical diagnostic laboratory performing full-gene sequencing and deletion/duplication analysis using next-generation sequencing technology (NGS).

Our sequence analysis covers clinically important regions of each gene, including coding exons, +/- 10 base pairs of adjacent intronic sequence, and select noncoding variants. Our assay provides a Q30 quality-adjusted mean coverage depth of 350x (50x minimum, or supplemented with additional analysis). Variants classified as pathogenic or likely pathogenic are confirmed with orthogonal methods, except individual variants that have high quality scores and previously validated in at least ten unrelated samples.

Our analysis detects most intragenic deletions and duplications at single exon resolution. However, in rare situations, single-exon copy number events may not be analyzed due to inherent sequence properties or isolated reduction in data quality. If you are requesting the detection of a specific single-exon copy number variation, please contact Client Services before placing your order.

Gene Transcript reference Sequencing analysis Deletion/Duplication analysis
PCBD1 NM_000281.3