19p13.2 microdeletions - Unique The Rare Chromosome Disorder ...
19p13.2 microdeletions - Unique The Rare Chromosome Disorder ...
19p13.2 microdeletions - Unique The Rare Chromosome Disorder ...
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One 16 year old girl started menstruating at aged 11 years. Another female, of unknown<br />
age, has secondary amenorrhea; this occurs when a woman who has been having normal<br />
menstrual cycles stops getting her periods for six or more months. A 16-year-old boy has<br />
low testosterone and is on testosterone injections to correct this imbalance (Decipher,<br />
<strong>Unique</strong>).<br />
Ongoing research involving <strong>19p13.2</strong><br />
<strong>The</strong> <strong>19p13.2</strong> region is located between 6.9Mb and 12.6 Mb on chromosome 19 (see<br />
diagram). <strong>The</strong> variation in size of the <strong>microdeletions</strong> (0.18Mb – 3.42Mb) within this region<br />
can mean anything from 7- 96 genes can be missing (see diagram below). Candidate<br />
genes that might play a part in the features associated with <strong>19p13.2</strong> microdeletion<br />
include:<br />
Insulin receptor and resistin: genes that could predispose to obesity as they regulate<br />
glucose (sugar) metabolism.<br />
PDE4A – an enzyme that has been linked to conditions that affect the brain such as:<br />
Alzheimer’s, Parkinson’s, bipolar disorder, mild learning disabilities, autism and<br />
depression.<br />
S1RPF, CDKN2D and AP1M2 – involved in the development of the brain<br />
(Haberlandt 2012, Wangensteen 2013)<br />
6,900 000<br />
7,000,000<br />
Some genes (and their base<br />
pair position) located on <strong>19p13.2</strong>:<br />
8,000,000<br />
9,000,000<br />
10,000,000<br />
11,000,000<br />
PDE4A (10,430,645-10,441,307)<br />
CDKN2D (10,538,138-10,540,655)<br />
AP1M2 (10,544,347-10,558,991)<br />
<strong>Chromosome</strong> 19<br />
12,000,000<br />
12,600,000<br />
As this is a gene-dense region, there are likely to be a number of different genes<br />
involved; the precise size and location of the deletion (see diagram) will govern which<br />
genes are deleted. It is also important to remember that, while identifying the gene(s)<br />
responsible for certain features of <strong>19p13.2</strong> microdeletion is valuable and may help guide<br />
future studies, it does not lead directly to immediate improved treatment. In addition,<br />
even if a gene is missing it does not always mean that the associated feature(s) will be<br />
evident or that there is a direct relationship between an absent gene and a particular<br />
feature. Other genetic and environmental factors often have a role in determining the<br />
presence or absence of a particular feature.<br />
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