BBC News website disability affairs reporter
Healthcare provision for people with learning disabilities and for people with mental health problems is to be investigated by the Disability Rights Commission (DRC).
The body - which oversees the rights of disabled people in the UK - is concerned that people with learning difficulties and mental health patients have significantly worse health than the rest of the population.
The DRC is concerned that some doctors only see a person's disability
Its investigation will focus on primary care - access to GP's, health screening services and health improvement initiatives.
The DRC says that initial research shows that:
People with learning disabilities are four times more likely to die as a result of a preventable condition
People with diagnosed schizophrenia die, on average, nine years before the rest of the population
Fewer than 20 percent of learning disabled women attend cervical screening
People with learning disabilities are 58 times more likely to die before the age of 50
The DRC is anxious to determine the causes of these health inequalities and will make recommendations about how they can be reduced when it reports in 18 months' time.
Among its areas of investigation will be whether healthcare professionals are failing to recognise problems, or diagnosing them too late.
Some people are not being included in health screening programmes
This is known as 'diagnostic overshadowing - whereby a patient's physical symptoms tend to be seen in terms of their mental health condition or learning disability.
The DRC will also be interested to determine whether some people experience difficulties registering or remaining with a GP practice.
"The government's commitment to improving the nation's health could risk leaving out significant groups in our population," said DRC chairman, Bert Massie.
"Unless the inequalities between people with learning disabilities, people with mental health problems and non-disabled people are seriously addressed, we could find the gap widening."
Mr Massie said the investigation was a positive opportunity to share concerns and best practice.
The Royal College of General Practitioners says it welcomes the DRC's inquiry.
"It is an important function of GP's to iron out health inequalities - we are committed to promoting excellent care for all patients what ever their needs," said Royal College chairman Mayur Lakhani.
The DRC will be gathering evidence from individuals and organisations about access to primary healthcare in England and Wales.
In addition to examining information already available, it says that four primary healthcare bodies will be independently monitored to identify the barriers confronting people with learning disabilities or mental health problems.
It is also opening a dedicated website where anyone with an interest in the issue can register their views.
Health Minister Stephen Ladyman said: "The Department of Health is aware that more work needs to be done in reducing health inequalities experienced by people with learning disabilities and people with mental health problems and have already agreed a framework with the Disability Rights Commission to shape the formal investigation."
Mr Ladyman said the department was also working with Mencap on a number of ideas for improving the health of people with learning disabilities, including the need for primary care services to proactively identify people's health problems.
A guide had also been issued to primary care professionals to share best practice.