Because he suffers from selective mutism, it's difficult for him to speak.

My grandmother is suffering from osteoporosis.

He always carries something sweet with him because of his hypoglycemia.

My friend is troubled by alopecia areata.

She suffers every month because of dysmenorrhea.

My dog recently contracted strongylosis.

His daughter was diagnosed with phenylketonuria.

Hypervitaminosis occurs when the intake of vitamins is too high.

He has prosopagnosia, which makes it very difficult to remember faces.

His long talk is just like 'a hundred days of sermonizing without a fart.'