Diencephalic Syndrome

Diencephalic Syndrome

National Organization for Rare Disorders, Inc.


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  • Diencephalic Syndrome of Childhood
  • Diencephalic Syndrome of Emaciation
  • Paramedian Diencephalic Syndrome
  • Russell's Diencephalic Cachexia
  • Russell's Syndrome

Disorder Subdivisions

  • None

General Discussion

The diencephalic syndrome is a very rare neurological disorder characterized by failure to thrive, abnormal thinness (emaciation), amnesia, intense sleepiness, unusual eye position and sometimes blindness. It is normally seen in infancy or early childhood but some cases have been reported in older children and even adults. Diencephalic syndrome is usually caused by a brain tumor such as a low-grade glioma or astrocytoma.


The diencephalic syndrome is a very rare disorder that usually affects young children. It can usually be recognized by three important features; failure to thrive, extreme thinness, and normal linear growth. Patients usually have a history of normal development and weight gain, followed by either a prolonged period of failure to gain weight or weight loss. The individual may have anorexia or even apparently excessive appetite. Over time, a loss of fat under the skin occurs with an associated emaciated appearance. The child may have a relatively large head, as compared with body weight. Overall development is often slowed, but neurological testing is normal. The eyes are often affected and the infant or child may have crossed eyes (strabismus), unusually rapid movements of the eyes (nystagmus), abnormal swelling of the eyes (papilledema) or vision loss. The child may be unusually sleepy and extremely thin. The child usually behaves in a normal, alert, happy manner that is not in keeping with their physical appearance. Height is normal or even above average but growth hormone plasma level is usually higher than normal.


Diencephalic syndrome usually results from the development of a brain tumor, often a low-grade glioma of the hypothalamic region or astrocytoma. The tumor may invade the anterior third ventricle of the brain or the optic nerve (chiasm) that causes elevated pressure in the skull.

The cause of the weight loss associated with the tumors is unknown, but may be due to a reduced appetite and/or a high rate of metabolism. Other possibilities are excessive growth hormone secretion, activation of proteins produced by the pituitary gland that break down fat, or the secretion of a yet-to-be defined fat mobilizing compound. There is no known genetic predisposition for diencephalic syndrome.

Affected Populations

Diencephalic syndrome is a very rare disorder that affects males and females in equal numbers. Usually the patient is a young infant or child between the ages of 18 months and 3 years of age but it can also develop in during later childhood or even adulthood. The syndrome occurs worldwide. Childhood brain tumors arise in 2.5-3.5 per 100,000 children per year.

Standard Therapies


The diagnosis of diencephalic syndrome is suspected in a child who has failed to thrive despite eating an apparently normal diet. A history of relatively normal development prior to the onset of weight loss and lack of clear-cut stomach or intestinal problems is suggestive of the diencephalic syndrome. A complete history and clinical evaluation by a physician who specializes in disorders of the brain and nervous system (neurologist) and imaging tests such as CT scans (computed tomographic scans) or MRI (magnetic resonance imaging scans) may help to confirm the diagnosis.


Treatment options are limited. Supplemental feeding alone is usually not helpful because the tumor will continue to grow and cause increasing emaciation. Extensive surgery has been reported to result in temporary tumor control, but total removal of the tumor is usually impossible because of its location and tendency to invade other tissues. The most common form of treatment has been biopsy and partial removal of the tumor followed by radiation therapy. More recently, chemotherapy has been reported to be effective in some children with diencephalic syndrome caused by low-grade gliomas.

Investigational Therapies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:


Several experimental drugs are being investigated for the treatment of brain tumors that may be associated with diencephalic syndrome. These include Interferon alfa-2b, serratia marcescens extract (polyribosomes), adenosine, borolife (sodium monomercaptoundecahydro-closo-dodecaborate), Liposome encapsulated recombinant Interleukin-2, and recombinant human Interferon Beta.

Biodegradable carmustine (biodel) is a plastic-like (polymer) implant that is being studied for treatment of malignant glioma. Photon therapy is a high beam form of radiation therapy being tested as treatments for brain tumors. More studies are needed to determine the long-term safety and effectiveness of these procedures for the treatment of diencephalic syndrome.



Packer RJ. Diencephalic Syndrome. In: The NORD Guide to Rare Disorders, Philadelphia: Lippincott, Williams and Wilkins, 2003:528-529.


Danoff BF, Kramer S, Thompson. The radiotherapeutic management of optic gliomas of children. Int J Radiat Oncol Biol Phys 1980;6:45-50.

Gropman AL, Packer RJ, Nicholson HS, et al. Treatment of diencephalic syndrome with chemotherapy. Cancer 1998;83:166-172.

Markesbery WR, McDonald JV. Diencephalic syndrome. A long-term survival. Am J Dis Child 1973;125:123-125.

Menzes AH, Bell WE, Perret GC. Hypothalmic tumors in children: their diagnosis and management. Child Brain 1977;3:265-280.

Scott EW, Mickle JP. Pediatric diencephalic gliomas: a review of 18 cases. Pediatr Neurosci 1987;13:225-232.

Meissner I, et al. The paramedian diencephalic syndrome: a dynamic phenomenon. Stroke 1987;18(2):380-385.


National Hydrocephalus Foundation

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Hydrocephalus Association

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Children's Brain Tumor Foundation

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Brain Tumor Foundation for Children, Inc.

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Tel: (404)252-4107

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Rare Cancer Alliance

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Genetic and Rare Diseases (GARD) Information Center

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Madisons Foundation

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Pediatric Brain Tumor Foundation

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National Brain Tumor Society

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For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into myCigna.com. For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html.

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