Can there be any disorder that makes someone not care for close relationships?

Yes. There's a continuum of preference for relationships. One one end is desire for constant togetherness, perhaps clinging and fear of separation. On the other end is complete alienation. You find gradations in between. Some disorders like schizoid & schizotypal pd have little desire for close relationships. Avoidant pd wants them, but fears them -- and so avoids them.