Final answer:
Tay-Sachs disease is caused by a single base-pair insertion or deletion mutation in the HEXA gene, which can result from DNA replication errors or environmental damage. It is an autosomal recessive disorder that leads to the destruction of neurons due to enzyme malfunction.
Step-by-step explanation:
A potential cause for a single base-pair insertion or deletion mutation in the HEXA gene, which causes Tay-Sachs disease, could be errors during DNA replication. Spontaneous mutations can also arise due to environmental factors such as exposure to radiation, certain viruses, or toxic chemicals such as tobacco smoke.
The mechanism behind this mutation involves the alteration of the DNA sequence, leading to a disrupted encoding for the alpha-subunit of beta-N-acetylhexosaminidase A. This enzyme is crucial for the breakdown of sphingolipids in neurons. A mutation affects the organelle's ability to perform its function, leading to the accumulation of sphingolipids and subsequent neuron damage.
Tay-Sachs disease is an autosomal recessive disorder, meaning that a child must inherit two copies of the mutated gene, one from each parent, to develop the condition. Carriers of one copy of the mutation do not exhibit symptoms but can pass the mutated gene to their offspring. This contrasts with autosomal dominant disorders, such as Huntington's disease, where the presence of just one mutated gene can lead to the disorder.