Higher birthweight 'linked to grandmother gene'

Scientists say a gene variation could contribute up to 155g (5.5oz) to a child's birthweight.

The gene studied is believed to act as a growth suppressor, reducing birthweight.

But the UK-based researchers found a particular variant passed down from the mother can add 93g (3.3oz) to the birthweight, or 155g if passed down from the maternal grandmother.

Details are published in the American Journal of Human Genetics.

Professor Gudrun Moore of University College London and colleagues looked at a gene called PHLDA2 in nearly 9,500 DNA samples taken from mothers and their babies, collected in three separate studies.

They found a gene variant called RS1 appeared to change the way in which the gene functioned, leading to higher birthweights.

"The gene is already known to have a profound effect on birthweight by acting as a growth suppressor," Prof Moore told BBC News.

"We have found a genetic variant of PHLDA2 that when inherited from the mother, causes the baby to be 93g bigger on average, or even 155g bigger on average, if inherited successively from the mother's mother."

The RS1 variation was found in around 13% of the individuals studied, with 87% possessing the RS2 variation.

"We suggest that the more common RS2 gene variation, which is only found in humans, has evolved to produce a smaller baby as a protective effect to enhance the mother's survival during childbirth," said Prof Moore.

"Dad's lack of involvement in evolutionary terms may stem from his own survival not being at stake and he can continue to reproduce with other females."

Gene 'silenced'
The PHLDA2 gene is unusual in that only the copy inherited from the mother is active, while the copy inherited from the father is "silenced". This silencing of the paternal gene results from molecular processes around the DNA known as epigenetics.

Scientists do not know why, but have speculated that it is to ensure birthweight is reduced to ensure the mother survives childbirth.

Dr Caroline Relton of Newcastle University said: "Although this study looks only at birthweight as an outcome, it is possible that this genetic variant may have longer-term health consequences.

"Indeed the long-term health consequences associated with extremes of birthweight might be due in part to this and other contributory genetic factors."

Obesity harms 'later brain skill'

Being overweight in later life puts you at higher risk of brain decline, Korean research suggests.

A study of 250 people aged between 60 and 70 found those with a high body mass index (BMI) and big waists scored more poorly in cognitive tests.

The Alzheimer's Society said the research, in the journal Age and Ageing, added to evidence that excess body fat can affect brain function.

Lifestyle changes can help make a difference, it said.

The study looked at the relationship between fat levels and cognitive performance in adults aged 60 or over.

The participants underwent BMI - a calculation based on a ratio of weight to height - and waist circumference measurements, a scan of fat stored in the abdomen and a mental test.

Both a high BMI and high levels of abdominal fat were linked with poor cognitive performance in adults aged between 60 and 70.

In individuals aged 70 and older, high BMI, waist circumference and abdominal body fat were not associated with low cognitive performance.

The lead author of the study, Dae Hyun Yoon, said: "Our findings have important public health implications. The prevention of obesity, particularly central obesity, might be important for the prevention of cognitive decline or dementia."

A spokesperson from the UK Alzheimer's Society said: "We have all heard how a high BMI is bad for our heart but this research suggests it could also be bad for the head.

"Although we don't know whether the people in this study went on to develop dementia, these findings add to the evidence that excess body fat could impact on brain function.

"One in three people over 65 will die with dementia but there are things people can do to reduce their risk.

"Eating a balanced diet, maintaining a healthy weight, exercising regularly and getting your blood pressure and cholesterol checked can all make a difference."

Whitney Houston Drowned After Cocaine Use

Whitney Houston's death was caused by accidental drowning, but drug abuse and heart disease were also factors, a coroner has ruled.

Coroner's spokesman Craig Harvey said drug tests indicated the 48-year-old US singer was a chronic cocaine user.

The announcement ends weeks of speculation over the cause of Houston's death.

She was found submerged in the bath of her Los Angeles hotel room on the eve of the Grammy Awards on 11 February.

In a statement, the LA County Coroner's office described Houston's manner of death as an "accident", adding that "no trauma or foul play is suspected".

The cause was cited as drowning and "effects of atherosclerotic heart disease and cocaine use".

Other drugs found in her blood included marijuana, as well as an anti-anxiety drug, a muscle relaxant and an allergy medication.

But these were not factors in her death, the coroner's statement said.

Patricia Houston, the singer's sister-in-law and manager, told the Associated Press news agency: "We are saddened to learn of the toxicology results, although we are glad to now have closure."

The pop star was laid to rest at a cemetery in her home state of New Jersey after a funeral that was attended by celebrities including Oprah Winfrey, Alicia Keys, Mariah Carey and Mary J Blige.

The singer, who was one of the world's best selling artists from the mid-1980s to late 1990s, had a long battle with drug addiction.