It is not yet known whether there is a typical behaviour pattern for children and adults with Kleefstra syndrome but children are generally described by their families as sociable, calm, fun-loving, loving and outgoing. Generally, children relate better to adults than other children and have little or no stranger anxiety and can be overfriendly. Problem behaviours including invading others’ space, aggression (biting, hitting, hair pulling) and unpredictable mood swings can occur as well as difficulties such as a high pain tolerance, being easily frightened, feeling insecure and disliking changes in routine.
A change in behaviour can be due to ill health but sometimes no cause can be found.
There are many reports in the medical literature of children with behaviour that families could find challenging. These range from chewing objects to self stimulatory behaviours (biting, hand in mouth and chomping), obsessive-compulsive disorders, stereotypic movements, outbursts of anger, self injury and aggression towards others. Many children with special needs, including those with Kleefstra syndrome, show behaviours that fall within the autistic spectrum. These range from repetitive behaviours and social incomprehension to a cyclical state of profound passivity diagnosed as autistic catatonia.
Puberty may bring a sudden increase in these hard-to-handle behaviours and moods. There is some recovery in adulthood but psychiatric care may be needed meanwhile.
Two children are reported to have seasonal affective disorder, with low mood and responsiveness throughout the winter and a recommendation of light therapy.
Parents should be offered full behavioural support. Some parents are reluctant to use medication for their child’s behaviour but the right medication in the right dose can be transformative.

Information reproduced with permission, from Unique's Kleefstra syndrome leaflet. 

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