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[Gm1 gangliosidosis types 1 and 2 (author's transl)]
Insights
This study describes two cases of GM1 gangliosidosis, a rare genetic disorder. Both patients exhibited severe neurological symptoms and biochemical evidence of GM1 ganglioside accumulation, confirming the diagnosis.
Area of Science:
- Biochemistry
- Genetics
- Neurology
Context:
- GM1 gangliosidosis is a lysosomal storage disorder.
- It results from mutations in the GLB1 gene, leading to beta-galactosidase deficiency.
- Accumulation of GM1 gangliosides causes progressive neurodegeneration.
Purpose:
- To present two cases of GM1 gangliosidosis.
- To detail the clinical, morphological, and biochemical findings.
- To confirm the diagnosis through enzyme activity and ganglioside analysis.
Summary:
- Two infants presented with psychomotor retardation, skeletal anomalies, and hepatomegaly (Case 1) or neurological deterioration and a cherry-red spot (Case 2).
- Necropsy revealed GM1 ganglioside deposits in various tissues (Case 1) and primarily in the central nervous system (Case 2).
- Biochemical analysis showed zero beta-galactosidase activity and significantly elevated GM1 ganglioside levels in brain tissue.
Impact:
- These findings contribute to understanding the spectrum of GM1 gangliosidosis.
- The study reinforces the diagnostic criteria for GM1 gangliosidosis.
- It highlights the importance of biochemical and ultrastructural analysis in diagnosing lysosomal storage disorders.
Abstract:
Two cases of gangliosidosis due to aggregates of Gm1 are described. The first patient was a female infant with noticeable retardation in psychomotor development, coarse facies, hepatomegaly, and X-rays showing skeletal anomalies in the large bones, vertebral column, cranium and ribs. She died at the age of 10 months of a septic condition. The second patient was a male infant; deterioration in psychomotor development was first noticed 8 months after birth and this progressed slowly to arrive at a vegetative state with convulsions and myoclonus. The child died at the age of 4 years. There were no signs of enlargement of visceral organs but a cherry red stain was observed in the ophthalmologic examination. In the first case, necropsy revealed the presence of a deposit substance in the histiocytes of the hepatic sinusoids, spleen, pancreas, thymus, septi and pulmonary alveoli, intestinal lamina propria, epithelial cells of the renal glomeruli, and in the neurons and glial cells of the brain. The same deposits were observed only in the neurons and glial cells in the second case. Ultrastructural examination showed the presence of typical cytoplasmic membranous bodies in the central nervous system of both patients. The beta-galactosidase activity in the urine of both patients during life was zero. There was a higher than normal total amount of gangliosides in brain tissue samples from both (1906.7 and 2459.9 NANA/g respectively) as compared with normal values (724.0). This increase was proportional to the rise in Gm1 ganglioside (76.8 and 89.6 percent molar respectively) as compared to control (27.0). These clinical, morphologic, and biochemical data characterize both types 1 and 2 of gangliosidosis due to Gm1 aggregates.