It has been speculated that compulsive hoarding may be inherited in some cases, with gene research lending some support to this suggestion.
People who compulsively acquire and hoard clutter to the extent that it impairs their daily activities are labelled "compulsive hoarders".
The condition may damage relationships, cut the individual off from society, and even endanger lives.
Hoarding often runs in families, but it is uncertain whether DNA is involved.
"People with this problem tend to have a first-degree relative who also does. So it might be genetic, or it might be a modelling effect," Live Science quoted Dr. Randy O. Frost, a psychologist at Smith College, Northampton, Massachusetts, as saying.
A team of researchers from Johns Hopkins University School of Medicine reported in March 2007 that a region on chromosome 14 might be linked with compulsive hoarding in families with obsessive-compulsive disorder (OCD).
The study analysed samples from 999 OCD patients in 219 families.
Families with two or more hoarding relatives showed a unique pattern on chromosome 14, while the other families' OCD was linked to chromosome 3.
Dr. Sanjaya Saxena, director of the University of California, San Diego, Obsessive-Compulsive Disorders Program, said that that was the third study to find genetic markers specifically associated with compulsive hoarding.
She wrote in a letter to the editor of the American Journal of Psychiatry: "Other studies have confirmed that compulsive hoarding is strongly familial. (This research) adds to the mounting evidence indicating that compulsive hoarding is an etiologically discrete phenotype."
Other researchers have found that compulsive hoarding involves a specific type of brain activity. Some brain-imaging studies have shown that compulsive hoarders have a different pattern of glucose metabolism in the brain than either healthy people or non-hoarding OCD patients.
Hoarding patients have significantly lower activity in the brain's dorsal anterior cingulate cortex than non-hoarding OCD patients, and a different pattern of cognitive deficits was found, such as more difficulty making decisions and impaired decision-making.
Saxena concludes: "Compulsive hoarding syndrome appears to be a discrete entity, with a characteristic profile of core symptoms that are not strongly correlated with other OCD symptoms, distinct susceptibility genes, and unique neurobiological abnormalities that differ from those in non-hoarding OCD."
Considering that OCD is a common feature of Tourette's Syndrome, Dr. Heping Zhang of Yale University School of Medicine looked at the DNA of siblings with suffering from it, and found significant links to chromosome 4, 5, and 17.
"Something at chromosome 14 may be associated with hoarding," says Randy Frost of Smith College.
Writing in the Spring 2007 New England Hoarding Consortium Newsletter, he said: "This could be a dramatic breakthrough in our understanding of hoarding. However, it is important to note that these studies are all preliminary with relatively small samples that don't fully represent the range of hoarding in the population. Furthermore, we also don't yet understand just what traits might be heritable. Perhaps it is something that underlies hoarding, like decision-making problems, and not hoarding itself that is inherited."
He stressed the need for much larger studies, drawn from the entire population of people who hoard, not just those who are already diagnosed with OCD.
He has even joined hands with Johns Hopkins experts to answer the question more conclusively.
He advises people with hoarding tendencies in the family to be open and honest with their children about the issue.
"People who can recognize and talk about their own hoarding problems are much better able to control them than people who can't," he said.