HPRT1 gene mutations that cause Lesch-Nyhan syndrome result in a severe shortage (deficiency) or complete absence of hypoxanthine phosphoribosyltransferase 1. When this enzyme is lacking, purines are broken down but not recycled, producing abnormally high levels of uric acid.
What is HPRT mutation?
Expand Section. More than 200 mutations in the HPRT1 gene have been found to cause Lesch-Nyhan syndrome. These mutations include changes in single DNA building blocks (nucleotides) or insertions or deletions of small amounts of DNA within the gene.
Is HGPRT and HPRT the same?
Hypoxanthine-guanine phosphoribosyltransferase (HGPRT) is an enzyme encoded in humans by the HPRT1 gene.
What is Cornelia de Lange syndrome?
Cornelia de Lange syndrome (CdLS) is a genetic condition present at birth. It’s characterized by numerous physical, intellectual and behavioral differences. Children with CdLS usually have low birth weight, are smaller in size and height and have a smaller head circumference (microcephaly).
Why is HPRT a housekeeping gene?
Due to the constant requirement for GTP, as both a nucleotide for DNA synthesis and as an energy moleule throughout the cell, HPRT is reliably produced as a housekeeping gene and is found in all somatic tissue in low levels.
What enzyme is elevated in Lesch-Nyhan syndrome?
Lesch-Nyhan syndrome is a rare inborn error of purine metabolism characterized by the absence or deficiency of the activity of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT).
How does BestKeeper work?
The BestKeeper algorithm calculates the stability of the candidate genes based on the SD of their Cq values, plus the coefficient of variance (CV), correlation coefficient (r), and the p-value (p) which are also very important parameters (Pfaffl et al., 2004).
How does geNorm work?
geNorm is a popular algorithm to determine the most stable reference (housekeeping) genes from a set of tested candidate reference genes in a given sample panel. From this, a gene expression normalization factor can be calculated for each sample based on the geometric mean of a user-defined number of reference genes.
What is hypoxanthine-guanine phosphoribosyltransferase (HPRT)?
Hypoxanthine-guanine phosphoribosyltransferase (HPRT) is the enzyme which catalyzes salvage of the purine bases guanine and hypoxanthine into their respective monophosphate nucleoside i.e., guanylic monophosphate (GMP) and inosine monophosphate (IMP).
What is the function of the HPRT gene?
The hprt gene codes for the HPRT enzyme. This gene is located on the X chromosome and is hemizygous in CHO cells ( hprt+/– ). This enzyme is involved in the purine recycling pathway.
What is the pathophysiology of HPRT deficiency?
In HPRT deficiency the underutilization of hypoxanthine and guanine leads to increased excretion of the degradation product uric acid, and the accompanying underutilization of PRPP gives rise to increased activity in the de novo pathway, increasing uric acid production.
Where is HPRT found in the human body?
HPRT is ubiquitously expressed in cells of the human body, with highest levels found in the basal ganglia. The subcellular localization is cytoplasmic.
