Learn About HO

A different kind of obesity

What is acquired HO?

Acquired hypothalamic obesity (acquired HO) is a condition that affects weight and hunger in many brain tumor survivors.

If you or someone you love is struggling with rapid weight gain, constant hunger, and fatigue, it could be acquired HO.

Family dinner scene. Image of brain that reads: MORE FOOD NOW. Actor portrayal.

“I went into surgery, and I came out, and it was like I was turned into a different person…mentally and physically.” -Brain tumor survivor living with acquired HO

Actor portrayals

What causes acquired HO?

Acquired HO is caused by injury to the hypothalamus, a key control center in the brain.

Common Causes:

Brain tumors (like craniopharyngioma)
Brain tumor treatment (like surgery or radiation)

Other causes:

Traumatic brain injury
Stroke
Other neurological conditions

Acquired HO is a distinct and diagnosable medical condition. It’s important to know that changes in weight or hunger associated with acquired HO are the result of an injury to your hypothalamus—not something you caused.

What makes it “acquired”? HO is acquired if it occurs because a person’s hypothalamus gets injured. If a person is born with a brain abnormality that causes HO, it is called "congenital" HO, though this is less common.

Father and daughter smiling and looking at each other. Actor portrayals.

You don’t have to navigate acquired HO alone.

A Rhythm Patient Education Manager (PEM)^* can provide one-on-one educational support to help you better understand acquired HO and prepare for conversations with your doctor.

Connect with Rhythm

Patient Education Managers are employees of Rhythm Pharmaceuticals and do not provide medical care or advice. We encourage you to always speak to your healthcare providers regarding your medical care.

What makes acquired HO unique?

Weight gain from acquired HO is directly linked to an injury to the hypothalamus that affects the brain’s ability to manage weight, hunger, and how calories are used.

Specific challenges of acquired HO

Increased
hunger

Decreased energy
expenditure

Weight gain that is rapid and sustained

Unlike in other types of obesity, two unique factors contribute to weight gain in acquired HO:

Hunger that can be constant and hard to control, which is called hyperphagia (pronounced hi-per-FAY-juh)
Decreased energy expenditure, which is when the body uses fewer calories than it should each day. You can also think of this as having a slower metabolism

These two factors can lead to weight increasing quickly and not responding to diet or exercise.

Learn more about what causes weight gain in acquired HO

Changes in hunger can vary from person to person

Most people with acquired HO experience some level of increased hunger, and around 70% experience the constant, hard-to-control hunger called hyperphagia. However, some people may not notice any change in hunger.

“Immediately after the surgery, I was ravenously hungry. I gained 20 pounds in two weeks, and that was on just what the hospital was feeding me. I was hungry a lot, and I have struggled with fatigue ever since then.”-Brain tumor survivor living with acquired HO

Acquired HO can impact many aspects of peoples’ lives

There’s more to acquired HO than just weight gain. Living with acquired HO can make day-to-day life emotionally and socially challenging. Acquired HO may also lead to an increased risk of various health problems over time.

Emotional burden

Frustration with difficulty losing weight
Poor body image
Fewer positive social interactions
Negative impact on mental health

Potential long-term risks

Diabetes
High blood pressure
Heart disease
Liver disease

Acquired HO is diagnosed by a doctor

Tell your doctor about the symptoms you experience. The earlier acquired HO is diagnosed, the sooner you and your doctor can make a plan to manage it.

Find a doctor who
specializes in acquired HO

The selection of a healthcare provider is an important decision that you should consider carefully. The Healthcare Provider Locator Tool is for information purposes only. The information in the Healthcare Provider Locator Tool is provided solely by the listed healthcare providers and has not been verified by Rhythm Pharmaceuticals. Rhythm Pharmaceuticals makes no representations or warranties regarding, and shall not be responsible for, the competencies or skill level of any of the providers listed on the Healthcare Provider Locator Tool or the quality of their care. Please see Terms of Use of the Healthcare Provider Locator Tool for more information.