Can normal sized people have a dwarf?

Yes: Dwarf is a term we do not use in medicine anymore because of its despective use outside of medicine, but it was used to describe proportionate short people( mainly pepople with growth hormone deficiency). Growth hormone deficiency can be hereditary bu it can also happen in a spontaneous mutation (no parent or family history).

Achondroplasia: Achondroplasia is a fairly common cause of short limb dwarfism. Most cases are the result of spontaneous mutations in the fgfr3 gene which causes abnormal cartilage development. This means that most patients with achondroplasia have parents of normal size. In those with known achondroplasia, there's a 50% chance of having a child with this disorder.