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Sandhoff disease
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Sandhoff disease

Sandhoff disease is a rare, inherited neurological disorder that progressively destroys nerve cells in the brain and spinal cord, presenting in infantile, juvenile, or adult forms.

Overview

Sandhoff disease is a rare inherited disorder that progressively destroys nerve cells (neurons) in the brain and spinal cord (central nervous system). This condition is classified into three major types based on the age at which signs and symptoms first appear: infantile, juvenile, and adult.

The infantile form of Sandhoff disease is the most common and severe form and becomes apparent in infancy. Infants with this disorder typically appear normal until the age of 3 to 6 months, when their development slows and muscles used for movement weaken. Affected infants lose motor skills such as turning over, sitting, and crawling. They also develop an exaggerated startle reaction to loud noises. As the disease progresses, children with Sandhoff disease experience seizures, vision and hearing loss, and intellectual disability. An eye abnormality called a cherry-red spot, which can be identified with an eye examination, is characteristic of this disorder. Some affected children also have distinctive facial features, enlarged organs (organomegaly), or bone abnormalities. Children with the infantile form of Sandhoff disease usually live only into early childhood.

The juvenile and adult forms of Sandhoff disease are very rare. Signs and symptoms are usually milder than those seen with the infantile form, although they vary widely. The juvenile form can begin between ages 2 and 10. Characteristic features include speech difficulties, loss of cognitive function (dementia), seizures, and loss of muscle coordination (ataxia). Adult Sandhoff disease is characterized by problems with movement and psychiatric problems.

Frequency

Sandhoff disease is a rare disorder; its frequency varies among populations. This condition appears to be more common in the Creole population of northern Argentina; the Metis Indians in Saskatchewan, Canada; and people from Lebanon.

Causes

Variants (also known as mutations) in the HEXB gene cause Sandhoff disease. The HEXB gene provides instructions for making a protein that is part of two critical enzymes in the nervous system, beta-hexosaminidase A and beta-hexosaminidase B. These enzymes are located in lysosomes, which are structures in cells that break down toxic substances and act as recycling centers. Within lysosomes, these two enzymes break down fatty substances, complex sugars, and molecules that are linked to sugars. In particular, beta-hexosaminidase A helps break down a fatty substance called GM2 ganglioside.

Variants in the HEXB gene disrupt the activity of beta-hexosaminidase A and beta-hexosaminidase B, which prevents these enzymes from breaking down certain molecules, including GM2 ganglioside. As a result, these compounds can accumulate to toxic levels, particularly in neurons of the brain and spinal cord. In particular, a buildup of GM2 ganglioside leads to the progressive destruction of these neurons, which causes many of the signs and symptoms of Sandhoff disease. The severity of the shortage (deficiency) of the beta-hexosaminidase A and B enzymes typically determines the age at which the features occur and the form of Sandhoff disease that develops.

Because Sandhoff disease impairs the function of lysosomal enzymes and involves the buildup of GM2 ganglioside, this condition is sometimes referred to as a lysosomal storage disorder or a GM2-gangliosidosis.

Sandhoff disease is one of three conditions caused by a buildup of GM2 ganglioside. The other two conditions are called Tay-Sachs disease and GM2-gangliosidosis, AB variant, which are caused by variants in other genes.

Learn More About the Associated Gene

  • HEXB

Inheritance

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have variants. The parents of an individual with an autosomal recessive condition each carry one copy of the altered gene, but they typically do not show signs and symptoms of the condition.

Other Names

  • Beta-hexosaminidase-beta-subunit deficiency
  • GM2 gangliosidosis, type 2
  • GM2 gangliosidosis, type II
  • Hexosaminidase A and B deficiency disease
  • Sandhoff-Jatzkewitz-Pilz disease
  • Total hexosaminidase deficiency

Frequently Asked Questions

Currently there is no cure, but supportive therapies can improve quality of life. Enzyme replacement therapy is experimental and not widely available; gene therapy trials are ongoing. Symptomatic treatments—such as antiepileptic drugs for seizures, physical therapy to maintain muscle tone, and speech therapy for swallowing difficulties—can help manage symptoms and prolong functional independence.
For seizures, a neurologist may prescribe a tailored antiepileptic regimen and monitor EEG regularly. Feeding challenges are addressed with a dietitian who can recommend thickened feeds or specialized formulas, and a speech‑language pathologist can teach safe swallowing techniques. Regular ophthalmologic exams monitor vision loss, while occupational therapy can assist with daily living skills as the disease progresses.
Diagnosis starts with a detailed clinical assessment followed by a blood test measuring hexosaminidase A and B enzyme activity. If enzyme levels are low, a genetic test for mutations in the HEXB gene confirms the diagnosis. In some cases, a skin biopsy or nerve tissue sample may be needed to measure enzyme activity directly.
Infants may appear normal for the first few months, but between 3 and 6 months they often show a noticeable slowdown in developmental milestones, such as delayed rolling over, sitting, or crawling. A sudden loss of previously acquired motor skills, an exaggerated startle reaction to loud noises, and the appearance of a cherry‑red spot on the retina during an eye exam are early red flags that warrant further evaluation.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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