From the Guidelines for the Celebration of the Sacraments with Persons with Disabilities (USCCB, 2017):

1. In the Sacrament of Matrimony, Christians signify and participate in the mystery of the unity and fruitful love which exists between Christ and his Church. They help each other attain holiness in their married life and in the rearing and education of their children (Order of Celebrating Matrimony, 8).

2. All persons who are not prohibited by law can contract marriage (c. 1058).

3. Pastors of souls should make the necessary provisions to ensure the inclusion of persons with disabilities in marriage preparation programs. Through this preparation, all couples may become predisposed toward holiness and to the duties of their new state. In developing diocesan policies, the local ordinary should consult with men and women of proven experience and skill in understanding the emotional, physical, spiritual, and psychological needs of persons with intellectual disabilities (cc. 1063.2; 1064). Including persons with disabilities in sponsor couple programs is an especially effective way of supporting both the needs and the gifts of couples preparing for marriage.

4. Couples with intellectual or developmental disabilities who believe they are called to the vocation of married life are encouraged to seek counsel by discussing the Sacrament of Matrimony with their families and pastors. For matrimonial consent to be valid, it is necessary that the contracting parties possess a sufficient use of reason; that they are free of any grave lack of discretion affecting their judgment about the rights and duties to which they are committing themselves; and that they have the mental capacity to assume the essential obligations of the married state (c. 1095). It is also necessary that the parties understand that marriage is a permanent union and is ordered for the good of the spouses and the procreation and education of children (cc. 1096; 1055.1). Pastors and other clergy are to decide cases on an individual basis and in light of pastoral judgment based upon consultation with diocesan personnel involved with disability issues and canonical, medical, and other experts.

A physical disability, in and of itself, does not necessarily constitute an impediment to marriage. Medical and canonical opinions should be sought in determining the presence of any impediments to marriage. It should be noted that paraplegia does not always imply impotence, nor the permanence of such a condition, and it is not in itself an impediment. In case of doubt concerning impotence, marriage may not be impeded (c. 1084.2).

5. Catholics who are deaf are to be offered the opportunity to express their matrimonial consent in sign language if sign language is their primary means of communication (c. 1104.2). Marriage may also be contracted with a sign language interpreter's assistance whose trustworthiness has been certified by the pastor (c. 1106). Likewise, those who are nonverbal or have minimal verbal communication ability should be offered the opportunity to express their matrimonial consent using the communication system with which they are most fluent.

This also applies to the marriage preparation process.