Tay-sachs syndrome (norman-wood syndrome; familial amaurotic idiocy; gangliosidosis gm2 type 1; hexosaminidase deficiency) 1

General: Similar to ceroid lipofuscinosis; autosomal recessive; occasional dominant inheritance; onset birth to 10 months; affects Jewish females; death during first 2 years; stored ganglioside (see Ceroid Lipofuscinosis); decreased hexosaminidase A localized to chromosome 15 (15q22-l5q25.1).

Ocular: Nystagmus; strabismus; whitish-gray macular area with cherry-red spot in the center; retinal pigmentary changes with involvement of the macula occasionally may be seen instead of the typical red spot; grayish coloration of the macula is due to the swollen ganglion cells in the perifoveal macular region; retinal vessels become narrowed; progressive ascending optic atrophy; cortical blindness by age 12 to 18 months with reactive pupils; deterioration of ocular motor function.

Clinical: Hyperacusis; mental retardation; convulsions; muscles, initially flaccid, becoming spastic with progression; infants normal at birth but fail to thrive after 4 to 8 months; hypotonia; death; occurs primarily in Jewish children; biochemical heterogeneity; absence of hexosaminidase A most common (type 1); absence of hexosaminidase A and B in Sandhoff variant (type 2); feeding difficulties; doll-like facies; fine hair; macrocephaly; abnormal acousticomotor reaction.

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