Child Neurology Net

Tay-Sachs

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Definition

One of the gagliosidoses, Tay-Sachs is due to the accumulation of GM2 ganglioside in the white matter of the brain. The disease is characterized by progressive degeneration of the CNS with cherry-red spot of the retina and no organomegaly.

Etiology/ Pathogenesis

Deficiency of hexosaminase A due to a mutation

CNS is only affected organ

Can have juvenile and adult forms, which are caused by partial enzyme deficiencies

Brain increases in weight and volume during the second year up to 2000g (1000 g normal), cystic degeneration is seen of the cerebral white matter, along with atrophy of the cerebellar hemispheres.

Cherry red spot on the macula are the result of retinal ganglion cells accumulating stored material around the fovea. The material appears gray, and the cells of the fovea remain their normal red color. As a result of these changes, optic atrophy and blindness develop.

Age of Onset

First few months

Classic Presentation

Patients are generally normal until 3-6 months of age, when they begin to exhibit motor regression with delay or loss of milestones. Patients become very sensitive to sensory stimulation such as noise, often responding with exaggerated startle responses. They become more irritable, exhibit poor head control, and cherry red spots can be found on exam.

Seizures develop at any time in the first 2 years, and are often myoclonic, although focal and generalized are also seen.

Rarer Symptoms

Usual Course

Tay-sachs is progressive, leaving patients unresponsive and severely impaired at 1 year of age, seizures usually develop by 2 years, and many patients do not survive to 5 years.

Genetics

Autosomal recessive

Gene frequency is 1:30 Ashkenazi Jewish, 1:300 otherwise

About 80% of patients are Jewish.

Groups at high risk

Diagnostic Testing

Lysosomal testing will reveal deficiency of hexosaminase A.

EEG may reveal the typical pattern of hypsarrhythmia or multifocal cortical spike discharges may be present. Focal and generalized motor seiures may also be evident

Differential

Things with cherry red spots- cherry-red spot myoclonus, farber lipogranulomatosis, GM1 gangliosidosis, GM2 gangliosidosis, metachrmatic leukodystrophy, niemann-pick disease, sialidosis type III

Treatment

Supportive

Misc

Websites with additional info

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Definition	One of the gagliosidoses, Tay-Sachs is due to the accumulation of GM2 ganglioside in the white matter of the brain. The disease is characterized by progressive degeneration of the CNS with cherry-red spot of the retina and no organomegaly.
Etiology/ Pathogenesis	Deficiency of hexosaminase A due to a mutation CNS is only affected organ Can have juvenile and adult forms, which are caused by partial enzyme deficiencies Brain increases in weight and volume during the second year up to 2000g (1000 g normal), cystic degeneration is seen of the cerebral white matter, along with atrophy of the cerebellar hemispheres. Cherry red spot on the macula are the result of retinal ganglion cells accumulating stored material around the fovea. The material appears gray, and the cells of the fovea remain their normal red color. As a result of these changes, optic atrophy and blindness develop.
Age of Onset	First few months
Classic Presentation	Patients are generally normal until 3-6 months of age, when they begin to exhibit motor regression with delay or loss of milestones. Patients become very sensitive to sensory stimulation such as noise, often responding with exaggerated startle responses. They become more irritable, exhibit poor head control, and cherry red spots can be found on exam. Seizures develop at any time in the first 2 years, and are often myoclonic, although focal and generalized are also seen.
Rarer Symptoms
Usual Course	Tay-sachs is progressive, leaving patients unresponsive and severely impaired at 1 year of age, seizures usually develop by 2 years, and many patients do not survive to 5 years.
Genetics	Autosomal recessive Gene frequency is 1:30 Ashkenazi Jewish, 1:300 otherwise About 80% of patients are Jewish.
Groups at high risk
Diagnostic Testing	Lysosomal testing will reveal deficiency of hexosaminase A. EEG may reveal the typical pattern of hypsarrhythmia or multifocal cortical spike discharges may be present. Focal and generalized motor seiures may also be evident
Differential	Things with cherry red spots- cherry-red spot myoclonus, farber lipogranulomatosis, GM1 gangliosidosis, GM2 gangliosidosis, metachrmatic leukodystrophy, niemann-pick disease, sialidosis type III
Treatment	Supportive
Misc
Websites with additional info