Mendelian disorders arise from single-gene mutations. Chromosomal disorders, such as Klinefelter's, Down's, and Turner's syndromes, result from atypical chromosome numbers. Specific types of congenital stationary night blindness are inherited via Mendelian patterns (autosomal dominant, autosomal recessive, or X-linked). Although Vitamin A deficiency can induce night blindness, inherited instances are Mendelian.