Down syndrome or Down's syndrome, is a congenital condition that typically gives rise to characteristic facial and physical features. Individuals with this condition may also suffer from a range of associated health problems, although the severity of these problems varies between individuals.

Some of the signs and symptoms of Down syndrome include:

Physical symptoms

• Upward slanting eyes with oblique fissures
• Abnormally small chin (microgenia)
• Flat nasal bridge and small nose
• Small mouth
• Enlarged tongue (macroglossia)
• Broad head and a round face
• Single fold across the palm (called the palmar crease )
• Increased space between the first and second toe (called the sandal gap)
• Broad hand with short fingers.
• Poor muscle tone
• Joint laxity
• Growth parameters including height, weight, and head circumference are smaller in children with Down syndrome.

Other symptoms

• Intellectual disability in most children with Down syndrome is mild (IQ 50 to 70) to moderate (IQ 35 to 50).
• Language skills and speech may be slow to develop. Reading and understanding are also delayed.
• Development of the fine motor skills may be delayed, as well as gross motor skills causing problems with sitting, standing, climbing and jumping, for example.
• Some children may also develop autism spectrum disorders or attention deficit hyperactivity disorder.
• Examples of severe conditions infants with Down syndrome may be at risk of include heart defects and intestinal abnormalities.