Understanding HH


The main function of the hypothalamus is homeostasis, or maintaining the body’s status quo. The hypothalamus is also the critical link between the endocrine and nervous systems and is involved in many functions of the autonomic nervous system, as it receives information from nearly all parts of the nervous system.
To maintain and regulate a complex “normal state”, the hypothalamus helps stimulate or inhibit many of the body’s key processes, including:

  • Heart rate and blood pressure
  • Body temperature
  • Fluid and electrolyte balance, including thirst
  • Appetite and body weight
  • Glandular secretions of the stomach and intestines
  • Production of substances that influence the pituitary gland to release hormones
  • Sleep cycles
  • Mediation of emotional responses
  • Sexual behavior and reproduction

Damage to the hypothalamus can produce complications with appetite and sleep, but because the hypothalamus affects so many different parts of the endocrine system, it can be hard to pinpoint whether the root cause of the issue is actually related to another gland. However, there are hormone and other tests that help shed light on which part of the body is the root cause.



In medical literature, Hypothalamic Hamartomas are sometimes referred to as benign tumors and other times described as a lesion in or around the hypothalamus. One point that is generally agreed upon is that they are often difficult to diagnose and even more difficult to treat. Some individuals can go years with very few symptoms, or ones that are so mild, they are often missed by both parents and medical professionals. However, for most people with HH, the most common symptoms are frequent daily gelastic seizures (spontaneous laughing, giggling and/or smirking) or dacrystic seizures (crying or grunting); developmental delays; and/or precocious puberty. These symptoms often start early in life – for some, they become apparent shortly after birth, but are frequently misdiagnosed. A misdiagnosis or delay in proper diagnosis may result in unnecessary procedures, a decline in the overall quality of life for the individual, and cognitive decline that cannot be regained. Treatments are now available for some patients that can eliminate or reduce the tumor in size; eliminate or significantly reduce the frequency of seizures; and halt cognitive declines.


Identify the


There is tremendous variability between individuals and their symptoms. However, many individuals experience some combination of the following:



For many individuals with HH, the first seizure to occur is the gelastic seizure. However, it is not uncommon for gelastic seizures to go undetected for years because of their unusual presentation.

Here are some examples of gelastic seizures:

Gelastic seizures are called the “laughing seizure” because they may look like bouts of uncontrolled laughter or giggling. However, the laughter-like sounds are often forced and combined with a facial contraction similar to a smile or smirk. In some children, the vocalization has a crying quality and the facial contraction resembles a grimace. These crying seizures are called dacrystic seizures. The gelastic seizures are not associated with any sense of well-being or delight for the individual, but instead can result in a feeling of fear or loss of control. Often the seizures go unrecognized until some other seizure type appears. Gelastics often occur as a child is falling off to sleep but can occur throughout the day and night. Infants and children will often be aroused out of sleep by a gelastic seizure, then settle down and go right back to sleep. Gelastics may present differently with each child; however, some commonalities are evident. There is often an aura, which may appear as a startle, or even a look of panic or fear. The eyes may seem vacant, dilate, or move up and to the left or right. Some children respond by seeking comfort from a parent or favorite toy for no apparent reason, others will run to a location where they feel safe. There often is a slight smile that seems somewhat forced and laughter or grunting that seems unusual or not appropriate at that time. In infants, there may be grunting and unusual squirming as well. Parents have reported gelastics occurring with their children that appear to be triggered by loud noises or fearful responses to sudden actions. Gelastic can also be triggered by excitement and anxiety. Many of the unusual behaviors associated with HH make diagnosis difficult. For many families, the initial incorrect diagnoses can include colic, acid reflux, Irritable Bowel Syndrome (IBS), or simply normal behavior for young children.

Gelastic seizures are rarely diagnosed at onset yet they begin in infancy in over one-third of documented patients. Gelastic seizures can occur with very high frequency and amazing regularity. Diagnosis is further complicated by the fact that electroencephalographic studies (EEGs) are often normal or only nonspecifically abnormal in children when only gelastic seizures are present. For many parents, when they hear a description of a gelastic seizure, they realize the activity was indeed there before, yet unrecognized as a seizure.

In many children, it is only with the development of the more devastating absence, complex partial, or generalized seizures that the diagnosis of HH is eventually made. The most dramatic and disabling seizures associated with HH are more generalized seizures – specifically grand mal seizures and drop attacks. Generalized seizures often appear after the onset of gelastic and complex partial seizures. When they do occur, they are often preceeded by an initial gelastic or complex partial seizure. It is usually when other seizure types begin, that behavior and cognitive issues become more obvious.

  • Absence (or petit mal) seizures typically last 2 to 15 seconds and can include staring, fluttering eyes, and automatisms (picking, lip smacking, swallowing, fumbling). Typically, there is no confusion following these seizures and activities are resumed without disruption.
  • Complex partial seizures typically last 1-2 minutes and may be companied by an aura and automatisms. The child may be unaware of their surrounds or experience amnesia during the seizure and be mildly or seriously confused and tired following an episode. However, it is not uncommon for complex partial seizures to be the first seizure type reported.
  • Generalized (or grand mal) seizures typically last 1 to 2 minutes although they can last longer. They are typically accompanied by a cry or fall. During the seizure the child’s body may become rigid or jerk. Amnesia during the seizure is not uncommon and typically the child will be confused and very tired requiring sleep afterwards.


Precocious Puberty

Precocious Puberty can occur in patients with HH. It is defined as unusually early onset of puberty (before age 8 for girls and age 9 for boys). It has been reported as early as infancy, in some cases. Precocious puberty can occur by itself, without seizures, or other neurological problems.

Cognitive Impairments

Individuals with seizures due to HH commonly display a wide range of cognitive impairments. Impairments may range from slight to severe. Most prevalent are problems with working memory, long-term retrieval, and processing speed, as well as visual and verbal learning and memory. The exact relationship between cognitive ability and the influence of seizure type, frequency, and onset is not well understood. There have been reported cases of patients with gelastic seizures and HH with normal cognitive functioning, yet these cases are less common. It is unclear at this point if size and attachment of the HH to the hypothalamus have a direct affect on cognitive functioning.

Compared to children, adults showing symptoms later in life appear to have less severe seizures, less severe learning and behavior difficulties, and better occupation and social connections.

Pallister-Hall Syndrome

Pallister-Hall syndrome is a less common genetic disorder that affects the development of many parts of the body. Most people diagnosed with this condition have extra fingers and/or toes (polydactyly) and the skin between some fingers or toes may be fused (cutaneous syndactyly). Pallister-Hall can result in an HH that is often large. However, epilepsy occurs less frequently and is reported to be relatively mild compared to individuals with HH alone.

Emotional and Behavioral Difficulties

In current research papers on HH and behavior, it has been suggested that several diagnostic terms have been applied to the types of behavior demonstrated by individuals with HH. These include; attention deficit behavior, autism spectrum disorder, Asperger’s disorder, depression, paranoid disorder and obsessive-compulsive disorder. Some children have significant difficulties controlling angry outbursts, aggressive tendencies and many have been described as having oppositional-defiant disorder. These angry outbursts are often referred to as hypothalamic rages. Rages often can be mistaken for “temper tantrums” however, they usually happen quickly and without an identifiable cause or provocation. Children with rages have been reported to hit, kick, bite, cry, throw objects and bang on walls or doors. They may take out their aggression on parents, siblings or other children in a classroom setting. What makes the actions different is that the child typically does not make eye contact or the eyes seem vacant, they initially may not be able to hear any commands and they often require time and space to calm down. Once the behavior begins to subside, the child may feel tired, and often times they will feel distressed at being unable to control their behavior. They often apologize or feel very guilty for what has just occurred. Some parents have reported that their child has no memory of the rage once it is over.

Other Potential Deficits or Delays

Research data, as well as family reports, include a variety of other issues possibly associated with HH. Speech and language delays have been reported as well as delays in mobility to include deficits in balance, coordination and walking during early development. Families have also identified poor social skills and limited peer interaction as issues they deal with on a daily basis. Whether this is due to the HH, seizure activity, medications, or other neurological factors is not clear at this time. Further research in these areas is critical to the full understanding of the many complexities of HH

Endocrine Disturbances

Some individuals may experience endocrine or hormonal disturbances as a result of HH. Some individuals may experience problems with bed wetting, or symptoms of an extreme or lack of thirst. Many individuals may experience weight gain with or without a voracious appetite.

Understanding the path to a


While the exact number of Hypothalamic Hamartomas cases worldwide is not known, HH is estimated to occur at the rate of 1 in 200,000 children and teenagers worldwide. This number may be understated due to the fact that the process of diagnosing HH is complex and often not well understood.


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Identify and understand


Treatment options for hypothalamic hamartomas (HH) have increased dramatically in the last 10 years. When deciding on a treatment, it is important to discuss all options, the associated risks, and compare that to the potential long-term benefits. Make sure all your questions get answered completely, and that you trust the team of doctors who will be with you throughout the course of treatment. If you have to travel to another medical center for surgery or treatment, it is important that you establish a good relationship with the doctors in your local area that will be responsible for any follow-up care or treatments.

Treatment options for hypothalamic hamartomas and the associated seizures currently include:
Antiepileptic drugs
Surgical treatments
Gamma knife radiosurgery (GKS)
MRI-guided Laser Thermal Ablation
Other alternative treatment options

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Hypothalamic Hamartoma


The cause of HH is not known. There are studies that suggest that somatic mutations in the GL13 gene may be responsible. Regardless of the cause, the resulting challenges can be difficult to manage. While an HH may be benign as far as cell growth is concerned, it’s impact on the individual and those involved with that person’s care is anything but benign. It is common for the disorder to progress as the individual ages and the seizures worsen, becoming longer and more involved, and more seizure types develop. The seizures are often poorly controlled or completely unresponsive to the standard seizure medications. It is often at this stage, with the increase in numbers and types of seizures, when individual show signs of progressive cognitive decline and severe behavior problems.


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Where to find help


We’ve compiled a list of hospitals offer services for HH patients. Some hospitals offer comprehensive multi-disciplinary care, while others offer very specialized treatments. Hope for HH does not endorse any hospitals or doctors or represent that this is a complete list of hospitals providing HH treatment and care.


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A closer look


These animations provide a unique look at hypothalamic hamartomas.

  • The Anatomy of Hamartoma
  • Transcallosal (TC) Surgical Approach to Hypothalamic Hamartomas

Courtesy of Barrow Neurological Institute


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