Modifier Genes Flashcards
Additional factors that may contribute to the phenotypic expression of single gene disorders include environmental factors & ____.
modifier genes
___ are genetic variants that can affect the manifestation of a disorder, for instance its age of onset, the range or severity of symptoms and the rate of disease progression.
Modifier genes
T/F. The products of modifier genes may alter the expression of a distant gene in many ways. These include effects on transcription, splicing and translation, in addition to effects on the encoded protein such as its post - translational modification, transport, secretion, activation & degradation.
True.
It is becoming increasingly recognized that many conditions that were previously regarded as being single - gene disorders are, in fact, actually ____, w/ the severity or range of the clinical manifestations being the result of a combination of several genetic loci.
oligogenic
____ may be regarded as those that alter the liability to develop the condition rather than altering the phenotypic expression of the disease.
Susceptibility genes
The candidate modifiers for the onset and variability of Huntington disease symptoms are currently regarded as being the gene encoding a transcriptional repressor known as ____ that interacts w/ the HTT protein within the nucleus; the glutamate receptor gene, ____ ; & the ____ gene, w/c encodes the ubiquitin carboxyl - terminal hydrolase L1.
corepressor C - terminal binding protein (CtBP)
Glutamate Ionotropic Receptor Kainate Type Subunit 2 (GRIK2)
carboxyl - terminal hydrolase L1 (DCHL1)
In the autosomal recessive condition cystic fibrosis, one of the modifier genes of pulmonary disease severity for w/c the evidence is greatest, is ____.
transforming growth factor β1 .
The risk of developing breast cancer in carriers of a BRCA2 mutation is now known to be modified by the presence or absence of a ____ single - nucleotide polymorphism in the germline DNA.
Fibroblast growth factor receptor 2 (FGFR2)
