A human has 23 chromosome pairs, of which one pair is a sex chromosome pair. The rest are called AUTOSOMAL. So a gene located on one of these 22 chromosomes is called an autosomal gene.
Some gene variants (alleles) are recessive; that means, you won’t see them ‘do anything’ in a person unless the person has two copies of the same variant, one in each chromosome in the pair. Other alleles are DOMINANT. That means even if you have this allele in only one of your chromosomes, its effects will be noticed in your body.
An AUTOSOMAL-DOMINANT gene means an allele which will take precedence, and whose effects will ‘come out’ in your life.