An OCD Collaborative Genetics Study was done by the Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine in March, 2007. Their findings suggest that a region on chromosome 14 is linked with compulsive hoarding behavior in families with OCD.
Sanjaya Saxena, M.D., Director of the UCSD Obsessive-Compulsive Disorders Program says in a letter to the editor of the American Journal of Psychiatry;
“The OCD Collaborative Genetics Study is the third study to find genetic markers specifically associated with compulsive hoarding, indicating that it is a distinct and heritable phenotype. Other studies have confirmed that compulsive hoarding is strongly familial and appears to breed true.”
From the earliest studies of hoarding, it has been clear that hoarding runs in families. Studies asking about family members have reported that 50 to 80% of people who hoard had first-degree relatives whom they considered “pack rats” or hoarders. In a more stringent test of the family connection, the Johns Hopkins OCD Family Study diagnosed hoarding in 12% of first-degree relatives of people who hoarded. Although lower than the self-reported frequency found in other studies, it was still significantly greater than that of relatives of people with OCD (3%). Other studies have found evidence indicating that hoarding is genetically influenced.
Sanjaya Saxena, M.D., says:
Genetic and family studies suggest that compulsive hoarding has a different pattern of genetic inheritance and comorbidity (coexisting illnesses) than other OCD symptom factors. The hoarding/saving symptom factor has a recessive inheritance pattern, whereas the aggressive/checking and symmetry/order symptom factors show a dominant pattern.
A genomewide scan conducted in sibling pairs with Tourette’s Syndrome (in which there is a very high prevalence of OCD symptoms) found that the hoarding/saving symptom factor was significantly associated with genetic markers on chromosome 4, 5, and 17. One study found that 16 of 19 OCD patients with prominent compulsive hoarding (84%) reported a family history of hoarding behaviors. In at least one a first-degree relative, while only 37% reported a family history of DSM-IV OCD.
A family study of OCD found that, compared with people with non-hoarding OCD, compulsive hoarders had a greater prevalence of social phobia, personality disorders, and pathological grooming disorders, These were trichotillomania, skin-picking, and nail-biting, and higher rates of hoarding and tics in first-degree relatives. These studies indicate that the compulsive hoarding syndrome may represent a distinct subgroup or variant of OCD that may be caused by different genetic and familial factors than non-hoarding OCD.
Randy Frost,PhD, says in the Spring 2007 New England Hoarding Consortium Newsletter:
In our first studies of hoarding we noticed a trend for this syndrome to run in families. Since then three genetics studies have appeared in the research literature, all suggesting that hoarding may be at least partly heritable. These studies start with select populations, like Tourette’s patients or OCD patients, and look for people who hoard.
One of these studies was done by the OCD Collaborative Genetics Study under the direction of investigators at the Johns Hopkins University Medical School. They found preliminary evidence that the genetic contribution to hoarding could be localized to a specific chromosome on the DNA chain. Something at chromosome 14 may be associated with hoarding. 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.
To more fully determine the heritability of hoarding a much larger study is needed, one drawn from the entire population of people who hoard. That is, the sample must represent all people with hoarding problems and not just those who are already diagnosed with OCD. To that end, we have joined forces with the Johns Hopkins group to study the genetics of hoarding. Our first attempt to obtain funds from NIMH for the project failed, but we will be trying again shortly.
At this point we have no markers for the development of hoarding. We don’t know who will and who won’t develop hoarding problems. The best advice we can give is to be open and honest with your children as they grow up about hoarding tendencies in the family. People who can recognize and talk about their own hoarding problems are much better able to control them than people who can’t. -R.Frost
While Dr. Tolin says people may be predisposed to compulsive hoarding, they most likely did not inherit it. “For a condition like compulsive hoarding to come about you probably have to have a person who has a certain set of inherited characteristics,” he says. “[But] then that person then has to in some way learn or pick up the behavioral pattern.” People can overcome their predisposed tendency to be messy or to hoard, Dr. Tolin says. “Biology is not destiny. Just because somebody has a genetic predisposition to develop a certain behavioral condition, that doesn’t mean they are doomed,” he says.
“Exactly what triggers hoarding compulsions
and desires is still under investigation. Like OCD, it may be related, at least in part, to genetics and upbringing.”
“But biology is not destiny. Just because somebody has a genetic
predisposition to develop a certain behavioral condition, that doesn’t
mean they are doomed.”
-David F. Tolin, Ph.D., founder of the Anxiety Disorders Center at The Institute of Living in Hartford, CT
“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.”
-Randy O. Frost, Ph.D. Smith College
The Genetics of Compulsive Hoarding
By Jane Collingwood
Gene link to compulsive hoarding
People who have a compulsive urge to collect and clutter their homes with junk can partly attribute their problem to genes, according to a British study.
Researchers from King’s College London used a twin study to find that genetic predisposition explained a large amount of the risk for compulsive hoarding - a mental health problem in which people have an overwhelming desire to accumulate items normally considered useless, like old newspapers or junk mail.
Of the more than 5000 twins in the study, roughly two percent showed symptoms of compulsive hoarding and genes appeared to account for half of the variance in risk.
Researcher Dr. David Mataix-Cols said it has long been known that compulsive hoarding tends to run in families.
But he told Reuters Health that what has not been clear is whether that pattern is due to genes or to something in the home environment, like parenting practices.
“Twin studies allow us to separate these two sources,” Mataix-Cols said.
The study, published in the American Journal of Psychiatry, included both identical and fraternal twins. Identical twins share all of their DNA while fraternal twins share roughly half of their genes, making them no more genetically similar than non-twin siblings.
If genes are a more important factor than shared environment in a given disorder, then identical twins would be more similar in their risk of the problem than fraternal twins would be.
Mataix-Cols and his colleagues found that among female identical twins, when one twin showed compulsive hoarding symptoms, the other twin also did 52 percent of the time. Among fraternal twins, that figure was 27 percent.
There was no evidence, however, that environmental factors shared by twins contributed to compulsive hoarding. Instead, “non-shared” environmental factors – those unique to individuals – seemed to be at work.
Past research has shown that many people with hoarding problems have a history of traumatic events, according to Mataix-Cols. In particular, they have elevated rates of sexual abuse and “loss” – of a loved one or a home, for instance.
“What the study suggests is that genes are important, but probably some environmental stressors are needed to cause or trigger the hoarding problem,” said Mataix-Cols, adding more research is needed into this topic.
He said the hope was to find better therapies for compulsive hoarding as behavioral therapy and antidepressants are now the main forms of treatment, but they have met with limited success.
Is Compulsive Hoarding a Genetically and Neurobiologically Discrete Syndrome?
American Journal of Psychiatry
Sanjaya Saxena, M.D.
Genetic and family studies suggest that compulsive hoarding has
a different pattern of genetic inheritance and comorbidity than other OCD symptom factors.
The hoarding/ saving symptom factor shows an autosomal recessive inheritance pattern and has been associated with
genetic markers on chromosomes 4, 5, and 17 (Zhang et al., 2002).
One study found that 84% of compulsive hoarders reported a
family history of hoarding behaviors in at least one first-degree
relative, but only 37% reported a family history of OCD.
(Winsberg et al., 1999)
From researchers in Spain:
Genetic susceptibility to obsessive-compulsive hoarding: the contribution of neurotrophic tyrosine kinase receptor type 3 gene.
Alonso P, Gratacòs M, Menchón JM, Segalàs C, González JR, Labad J, Bayés M, Real E, de Cid R, Pertusa A, Escaramís G, Vallejo J, Estivill X.
OCD Clinical and Research Unit, Psychiatry Department, Hospital Universitari de Bellvitge, Feixa Llarga s/n, L’Hospitalet de Llobregat, Barcelona, Spain.
Recent work suggests that neurotrophic factors may contribute to the genetic susceptibility to obsessive-compulsive disorder (OCD). Among other clinical dimensions, the presence of hoarding obsessions and compulsions has been shown to be correlated with a number of clinical and neuroimaging findings, as well as with a different pattern of genetic inheritance.
We used a linkage disequilibrium (LD)-mapping approach to investigate whether neurotrophic tyrosine kinase receptor type 3 (NTRK3), the high-affinity receptor of neurotrophin 3 (NT-3), plays a role in increasing susceptibility to hoarding in OCD. We performed an association study of 52 tag single nucleotide polymorphisms (tagSNPs) covering the whole NTRK3 gene in a sample comprising 120 OCD patients and 342 controls. Single nucleotide polymorphism association and haplotype analysis were performed.
Thirty-six of our patients (30%) exhibited significant hoarding obsessions and compulsions. A significant association of two SNPs in the 3′ downstream region of NTRK3 gene and obsessive-compulsive hoarding was identified: rs1017412 [odds ratio (OR) = 2.16; P = 0.001] and rs7176429 (OR = 2.78; P = 0.0001), although only the latter remained significant after Bonferroni correction. Although the haplotype analysis did not show significant results, a more extended block of LD in the OCD hoarders with respect to the control group was observed, suggesting a lower haplotype diversity in these individuals.
Our findings suggest that NTRK3 may contribute to the genetic susceptibility to hoarding in OCD and may constitute an interesting gene to focus on in studies of the genetic basis of obsessive-compulsive hoarding.