<prompt> All are common in Down syndrome, except ?Simian creaseClinodactylyMothers age 35 yearsRespiratory tract infection uncommon  <response>: Ans. is d i.e., Respiratory tract infection uncommon Chronic rhinits, conjunctivitis and periodontal disease are common in Downs syndrome. Lower respiratory tract infections pose a threat to life. Pneumonias are common in patients with Downs syndrome. 