Three-year-old Kasan Allison idolizes his older brothers, Keenan and Kylan, likes to play games with his dad, Dave, and is always on the go, a toy tractor or his best bud, Mickey Mouse, in hand. When he’s unsure about something, he reaches for his mom, Amie, and he loves macaroni and cheese.Almost from the day Kasan was born, his parents recognized differences in his development. He did not lift his head, roll over, start crawling when his older brothers had.The Allisons didn’t know it at the time, but Kasan has XXXXY, commonly called 49 Chromosome Syndrome, and the chromosomal abnormality affects not only his life, but his family’s too.