I see a couple of questions here.
Having a medical condition is not a sin, even if it causes problems or embarrassment. For example, being too sick to attend Mass on Sunday does not mean that you have committed the sin of missing Mass. It means you were too sick to go. A medical condition is not a sin.
The second question seems to do with the cumulative effect. First no matter how many venial sin you commit, they never add up to a mortal sin. Likewise, no matter how many morally neutral acts you perform, they also never add up to sin.
The only cumulative effect of sin or questionable actions is the overall effect they have on behavior. Someone who habitually commits a particular venial sin may find their ability to overcome the temptation for mortal sin weakened, often significantly.
Finally, there is one important aspect to sin that cannot be forgotten. A person must choose to sin. One never sins accidently. Sin can be habitual, however. Also, people can blind themselves to the sins they commit because they do not have a properly formed conscience.