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Unformatted text preview: system disorder
• Due to mutation of the Hex A gene
• Incidence in general U.S. population: 1/320,000
• Incidence in the Ashkenazi Jewish population: 1/3500 Example of an Autosomal Recessive Trait • Tay-Sachs Disease: • Babies become listless and weak at about 6 months
• Physiological and neurological condition worsens
• Death at 2-3 years.
• There is no cure or treatment. Example of an Autosomal Recessive Trait
• Mechanism of Tay-Sachs:
• Accumulation of a lipid in the brain (GM2 ganglioside).
• Affected children are missing the enzyme necessary to break it
down (hexosaminidase A).
• Accumulates in the brain, causing swelling and other
symptoms. • Heterozygotes make half as much enzyme, but it is enough normal. Autosomal Dominant Traits
• Do not skip
• Equal number of
affected males and
females Autosomal Dominant Traits
IF HETEROZYGOUS, OBLIGATE CARRIER • Most affected
• ~1/2 the offspring of
an affected individual
are affected Example of an Auto...
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