Tay-Sachs Disease - Pathophysiology, Signs & Symptoms, and Diagnosis

Sep 27, 2026

Uploaded by OmBimo

Tay-Sachs disease results from a genetic mutation in the HEXA gene, leading to severe Hexosaminidase A deficiency and accumulation of GM2 ganglioside in cells. The condition shows classic histologic findings of distended lysosomes with an “onion skin” appearance and a cherry red macula on physical examination. Progressive neurodegeneration produces developmental delay and deterioration of mental and physical abilities beginning around 6 months. Diagnosis involves characteristic fundoscopic and histologic/electron microscopy features.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages2

Reading Time5 min

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Pathophysiology

Autosomal recessive inheritance

Hexosaminidase A deficiency

GM2 ganglioside accumulation

Signs and symptoms

Cherry red spot on macula

Neurodegeneration

Developmental delay

Diagnosis

Onion skin lysosomes

Tay-Sachs Disease Tay Sachs Disease is caused by a genetic mutation in the Hexosaminidase A gene, which causes accumulation of GM2 ganglioside in cells. There is an increased disease prevalence in the Eastern European Ashkenazi Jewish population. On histologic exam, neurons are ballooned with cytoplasmic vacuoles due to markedly distended lysosomes filled with gangliosides, which resemble an onion skin appearance. On physical exam, a cherry red macula can be appreciated. The disease also causes progressive neurodegeneration due to accumulation of the GM2 ganglioside and patients display progressive deterioration of mental and physical abilities at around 6 months of age. PLAY PICMONIC Pathophysiology Autosomal Recessive Recessive-chocolate Tay-Sachs Disease is inherited in an autosomal recessive modality. This means two copies of the abnormal gene must be present in order for the disease to develop. Hexosaminidase A Deficiency Broken Hexagon-mini-As Hexosaminidase A (also known as beta hexosaminidase A or HEXA) is an enzyme which is severely deficient in Tay-Sachs. This enzyme is responsible for breaking down GM2 ganglioside. Increased GM2 Ganglioside Up-arrow GM (2) Tutu car with Gangster-on-side This is the specific type of ganglioside that accumulates in Tay-Sachs. More Common in Ashkenazi Jewish Population Yarmulke (Yamaka) There is increased disease prevalence in the Eastern European Ashkenazi Jewish population. Signs and Symptoms Cherry Red Spot on Macula Cherry-eyes On fundoscopic examination, a small red spot is seen in the center of the macula of the retina. It is caused by accumulation of GM2 ganglioside in the retina and the relative transparency of the macula. This is seen in several different lipid storage diseases. Neurodegeneration Degenerating-nerve-arm Progressive deterioration of the central nervous system due to accumulation of GM2 ganglioside. Developmental Delay Developmental-bus Progressive deterioration of mental and physical abilities is seen at around 6 months of age due to harmful quantities of gangliosides that accumulate in the brain's nerve cells, leading to premature cell death. Diagnosis [Sign up for FREE at](Sign up for FREE at picmonic.com)[ picmonic.com](Sign up for FREE at picmonic.com) Onion Skin Lysosomes Onion-head On histologic exam, neurons are ballooned with cytoplasmic vacuoles that constitute a markedly distended lysosome filled with gangliosides. On electron microscope, several cytoplasmic inclusions make the appearance of an onion skin. [Sign up for FREE at](Sign up for FREE at picmonic.com)[ picmonic.com](Sign up for FREE at picmonic.com)

FAQs

What genetic defect causes Tay-Sachs disease?

Tay-Sachs disease is caused by a genetic mutation in the Hexosaminidase A (HEXA) gene.

How does Hexosaminidase A deficiency lead to disease symptoms?

Hexosaminidase A is responsible for breaking down GM2 ganglioside; when it is severely deficient, GM2 accumulates in cells, causing progressive neurodegeneration.

What physical and histologic findings are characteristic of Tay-Sachs disease?

Physical exam can show a cherry red macula, while histologic examination reveals neurons ballooned with cytoplasmic vacuoles from markedly distended lysosomes, with an “onion skin” appearance.

Sep 27, 2026

Uploaded by OmBimo