Children with RTS usually have a normal birth weight, but subsequent growth is poor, with most children being of short stature with a small head size. Problems that may occur in early life include breathing difficulties, feeding problems, poor weight gain, recurrent infections, and constipation.
Developmental delay occurs in most children with RTS. Most people have moderate to severe learning difficulties, although a few have mild learning difficulties (see entry Learning Disability). They may have particular problems with expressive language and often benefit from using sign language. Most children become self-sufficient in eating, dressing and toileting.
Usually individuals with RTS have friendly and sociable personalities; however, many will find change in routine difficult and show signs of autistic behaviour. Other behavioural problems may include poor concentration, reduced tolerance to noise and crowds, impulsive behaviour, instability of mood and high pain tolerance. Some will show self-stimulatory behaviours, such as rocking and hand-flapping.
Individuals with RTS tend to be shorter than average and often become overweight. This can contribute to sleep apnoea (difficulty breathing when asleep), which they are prone to due to having a narrow palate, micrognathia (small chin) and hypotonia (floppiness).