What is Gangliosidosis GM2?
GM2 gangliosidosis is a progressive neurodegenerative disease from the group of gangliosidosis, which in its classic infantile form usually leads to death at the age of 2–3 years.
The incidence is much higher among Ashkenazi Jews (Eastern Europeans).
Causes of Gangliosidosis GM2
Hexoaminidase A and / or B deficiency, as well as the hexoaminidase activation factor. The type of inheritance of all types is autosomal recessive.
Pathogenesis during Gangliosidosis GM2
There is a three-pointed model explaining the molecular genetic basis of GM2 gangliosidosis. Mutation of the hexosaminidase A gene (a-locus of chromosome 15q) underlies Tay-Sachs disease and juvenile GM2-gangliosidosis. The mutation in the b-locus of the 5th chromosome is manifested by the deficiency of hexosaminidase A and B and causes GM2-gangliosidosis type II (Sandhoff’s disease).
Symptoms of Gangliosidosis GM2
There are the following options for the course of the disease:
- Option 0 (268800, r) is Sandhoff’s disease. Clinically: weakness, muscle atrophy, startle response to sound, progressive psychomotor deterioration, cerebellar ataxia, dysarthria, fasciculation, pyramidal insufficiency, increased reflexes, orthostatic hypotension, macrocephaly, puppet face, early blindness, cherry-red spot on the ocular base, macroglossia, cardiomegaly, high lumbar hump, chronic diarrhea, episodic abdominal pain, hepatosplenomegaly, impaired sweating, urinary incontinence.
- Option B (* 272800, r) – Tei – Sachs disease of type 1. Clinically: the response to sound in the form of startles; muscular hypotonia, later turning into hypertonus, apathy, psychomotor delay, convulsive seizures, paralysis, dementia, a cherry-red spot on the fundus, surrounded by a light gray area; blindness, beginning in early childhood, death before the age of 5.
- Option AB (* 272750, r) – Tay – Sachs disease of type 2.
- Option A (M) B (230710, r) – Thay – Sachs disease is juvenile. Beginning at the age of 2 years, death by 8 years, delayed motor functions, mental development, muscle atrophy, spasticity, delayed speech development.