Divorce/annullment on grounds of rare diseases

Appears to be not possible.  Annulment cannot be granted by mere existence of rare disease in the respondent.  If petitioner takes the plea that this fact has been kept secret at the solemnization of marriage, within one year from the date of marriage or within one year from the date of knowing about this fact has to file annulment petition on the ground of concealment of material fact, but the chances of succeeding are weak.  In divorce, it is not at all possible.  Divorce can be granted only if the respondent suffers for mental disorders and incurable leprosy or virulent form of venereal disease in communicable form.  Not for unknown rare disease.