Save 20% on your next Cambridge Bioethics and Law online purchase
Page URL: https://www.bionews.org.uk/page_95103

New, single-gene form of obesity and diabetes identified

6 July 2015
Appeared in BioNews 809

A new form of obesity and type 2 diabetes that is caused by a mutation in a single gene has been discovered.

This finding adds to the existing list of over 30 single-gene mutations that individually cause obesity, type 2 diabetes or both.

Professor Alexandra Blakemore of Imperial College London and a lead author of the study, said: 'There are now an increasing number of single-gene causes of obesity and diabetes known. We don't know how many more have yet to be discovered, or what proportion of the severely obese people in our population have these diseases  it is not possible to tell just by looking.'

In the study, published in PLOS ONE, the researchers analysed the genome of a young woman with morbid obesity and newly diagnosed type 2 diabetes. She also had a condition affecting her fertility and some learning difficulties. They used a shortcut called exome sequencing, which looks at just that one percent of a person's DNA that encodes proteins.

They found that the patient had inherited two mutated copies of the carboxypeptidase E (CPE) gene. The CPE protein is an enzyme that processes various hormones and chemical messengers called neuropeptides, which mice studies had previously shown to control appetite and insulin, among other roles.

Looking at the genomes of the patient's family who did not have the same symptoms, they also found that some close relations including her mother had one copy of the mutation. One of the patient's sisters, who had a single copy of the mutated CPE gene, was found to have lower levels of the CPE enzyme in her blood. The patient also had an older brother, who died aged 21 and who had shown similar symptoms.

The parents of the patient are first cousins, which increases the likelihood that two copies of a rare mutation such as this will be passed on.

The researchers noted previous research which showed that mice with mutations in the mouse equivalent of the CPE gene, or which had that gene removed, also developed obesity, infertility and disturbed insulin levels.

Type 2 diabetes is a condition in which the body does not produce enough insulin, or does not respond properly to insulin, leading to a dangerously high levels of glucose in the blood. Having a close relative with type 2 diabetes increases the risk of developing the condition, indicating that genetics is a significant factor.

The team is hopeful that knowing when conditions are caused by genetic factors will be helpful for patients. 'Finding a genetic cause for the patient's problems has helped her and her family to understand and manage her condition better,' said Dr Sanne Alsters, also of Imperial College, who carried out the genetic analysis. 'We can also look at members of her family with one abnormal copy of the gene, to see they are affected in more subtle ways that could increase their risk of obesity.'

RELATED ARTICLES FROM THE BIONEWS ARCHIVE
3 April 2017 - by Dr Marianne Kennedy 
Seventy-nine rare genetic syndromes in which obesity is a major feature have been catalogued by Canadian researchers...
26 September 2016 - by Hannah Somers 
People carrying a gene variant linked to weight gain can benefit from weight-loss programmes just as much as those without it, research from Newcastle University has shown...
1 August 2016 - by Rachel Reeves 
A newly discovered genetic variant in the Samoan population increases obesity risk by 35 percent – the largest effect of any obesity gene...
7 March 2016 - by Paul Waldron 
A study in mice has shown that a diet high in fat can stimulate the production of stem cells in the intestine, which might then go on to form tumours...
16 February 2015 - by Kirsty Oswald 
A meta-analysis has found that around a fifth of variation in BMI is due to common genetic variation...
16 February 2015 - by Dr Charlotte Warren-Gash 
Obese female mice have lower fertility than healthy weight mice, according to a study led by researchers from the University of Adelaide in Australia...
10 November 2014 - by Dr Charlotte Warren-Gash 
Our genetic make-up influences the type of bacteria that live in our gut, which in turn influences how likely we are to be overweight, a twin study has found...
2 June 2014 - by Alice Plein 
A common genetic mutation linked to childhood obesity also increases the likelihood of becoming overweight in adulthood, scientists have discovered. They found the genetic variation also increases impulsive eating as well as a person's appetite for fatty foods...
7 April 2014 - by James Brooks 
Obesity might not simply be a matter of overeating or heightened appetite but at least partially down to how we metabolise food, a study says...
HAVE YOUR SAY
What kind of medication would actually be the best to balance the insulin dependent? (User:118321 - 05/08/2015)
Since the diabetes cause are unknown, while so many risk factors like obesity, abnormal blood lipids, hypertensions have been identified that increases by certain variants HLA-DQA1, HLA-DQB1, and HLA-DRB1 genes wchich belong to HLA (Human Leukocyte Antigen) complex & play a critical role in our immune system.
Is genetic conditions are different or common between diabetes mellitus and cardiovascular disease going through such risk factors mentioned above? If it is so then what activities do we need to follow to balance the doses of insulin either with the food we eat or with the medication we are prescribed?
Log in to add a Comment.

By posting a comment you agree to abide by the BioNews terms and conditions


Syndicate this story - click here to enquire about using this story.