Temperature Sensitivity in Angelman Syndrome
On occasion, caregivers of children with Angelman syndrome report a sensitivity to changes in temperature, especially warmer temperatures.
Here is information about temperature sensitivity, and why it might be evident in these patients.
What is Angelman syndrome?
Angelman syndrome is a rare genetic disorder caused by mutations related to the UBE3A gene that resides on chromosome 15. The UBE3A gene contains instructions necessary for cells to make the ubiquitin-protein ligase 3A (UBE3A) enzyme. This enzyme plays a role in a pathway that labels proteins for cells to break them down.
People generally receive two copies of each chromosome, which contain their genes: one from their mother and one from their father. In certain types of cells, only one copy of a chromosome may be active — a process called genetic/genomic imprinting. In many cells of the nervous system, only the maternal copy of the UBE3A gene is active. So mutations or deletions in this gene’s maternal copy can lead to missing or dysfunctional UBE3A. Researchers think problems with this enzyme affect the growth and development of nerve cells, leading to disease symptoms.
In rare instances, a child may receive two copies of chromosome 15 from their father and have no maternal copy. This is called uniparental disomy, and is also disease-causing.
How does the body regulate temperature?
The hypothalamus, a part of the brain, regulates internal body temperature. When receptors in the body sense that the temperature is becoming too low or too high, the hypothalamus causes the body to adjust.
If your internal temperature is too high, the hypothalamus stimulates blood flow to the skin to release heat. People also sweat more, and increased sweat production helps to absorb the heat.
If your internal temperature becomes too low, the hypothalamus stimulates muscles to contract. The act of shivering increases heat production. Blood flow to the skin and extremities also decrease, reducing heat loss.
Temperature sensitivity in Angelman syndrome
Most reports of temperature sensitivity in Angelman patients, particular to warm room temperatures, are anecdotal reports. Caregivers, especially parents, have mentioned a patient’s skin being unusually warm, or a child becoming irritable or hyperactive in warmer settings. In very few instances, body temperatures dropping too low (hypothermia) are also reported. Hypothermia events are usually associated with the use of multiple medications or an illness, and typically resolve within a day or two.
A case study reported an Angelman infant and a toddler who both experienced long-lasting fevers. No infections or inflammation were found in either child. Researchers indicated their high temperatures may be related to problems with the hypothalamus and its ability to regulate body temperature.
Studies show a lack of UBE3A in cells of the hypothalamus in mice models of Angelman syndrome. This could lead to an impaired hypothalamus and difficulties with internal temperature regulation. It is not clear, however, whether the same is true in people with Angelman syndrome.
Tips to help with temperature sensitivity
Since temperature control may be poor in Angelman patients, caregivers should avoid overdressing them and ensure adequate hydration, especially in warmer areas.
Swimming and water play may be other good ways to help these patients cool off, especially as studies suggest their fascination with water.
In warmer climates or seasons, it may also be helpful to use air conditioning to keep rooms cool.
Last updated: Oct. 26, 2020
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