Individuals with a 15q13.3 microdeletion may experience a wide variety of clinical features, ranging from non-symptomatic to severe disability. In this overview the most frequent symptoms are listed. For more detailed information we refer to genereviews.
Developmental delay Learning difficulties and intellectual disability has been observed in about half of the individuals with a 15q13.3 deletion.Developmental delays are mainly delays in speech acquisition and cognitive function rather than motor disability. In the majority of individuals, cognitive impairment is mild. However, a subset of individuals with moderate to severe disability have been reported.
Epilepsy. The 15q13.3 microdeletion has been shown to represent a major risk factor for epilepsy, found in 1%-2% of individuals with generalized epilepsy. Epilepsy has been described in almost one third of individuals reported to have the 15q13.3 microdeletion.Various types such as absence seizures, myoclonic seizures, and primary generalized tonic-clonic seizures have been reported.
Neuropsychiatric disorders. Behavioral problems are relatively common and mainly include poor attention span, hyperactivity, mood disorder, and aggressive and/or impulsive behavior. Autism or autistic behavior has been reported in over 10% of persons with the 15q13.3 microdeletion and can be present in both intellectually disabled and non-disabled individuals.
Other features In general, individuals with the 15q13.3 microdeletion have no or only mild dysmorphic features. In three reports cardiac defects were noted in 7%-17% of individuals, whereas cardiac evaluation of persons with the deletion was not mentioned in other reports. Whether 15q13.3 deletions are associated with cardiac defects is still uncertain. Other frequently occurring congenital anomalies have not been reported.