Final answer:
In a sample taken from a patient with ataxia-telangiectasia, one would expect to observe a decreased DNA repair capacity due to a mutation in the ATM gene, leading to increased sensitivity to DNA damage and a higher cancer risk.
Step-by-step explanation:
When examining a sample from a patient with ataxia-telangiectasia, one would expect to find a decreased DNA repair capacity. Ataxia-telangiectasia is a condition that affects the DNA repair pathways, which are crucial for correcting errors in the DNA sequence. This condition is marked by a mutation in the ATM gene, which is critical for cell cycle control and DNA repair. As a result, individuals with ataxia-telangiectasia exhibit increased sensitivity to ionizing radiation and a predisposition to cancer due to their cells' inability to adequately repair DNA damage.
A decreased capacity for DNA repair can lead to the accumulation of mutations within the genome. Over time, the persistence of these mutations can generate a variety of health problems, including neurodegeneration and a higher risk of developing malignancies. Unlike cancerous cells, which might show enhanced cell division due to activated telomerase after telomere shortening, in ataxia-telangiectasia the primary issue lies in repairing DNA, not uncontrolled proliferation.