16p11.2 duplication

Also known as: 16p11.2 duplication syndrome; 16p11.2 microduplication; autism, susceptibility to, 14B; AUTS14B


Genetics Home Reference

16p11.2 duplication is a chromosomal change in which a small amount of genetic material within chromosome 16 is abnormally copied (duplicated). The duplication occurs near the middle of the chromosome at a location designated p11.2. This duplication can have a variety of effects. Common characteristics that occur in people with a 16p11.2 duplication include a low weight; a small head size (microcephaly); and developmental delay, especially in speech and language. Affected individuals also have an increased risk of behavioral problems. However, some people with the duplication have no identified physical or behavioral abnormalities.

Developmental delay and intellectual disability can occur in people with a 16p11.2 duplication. Approximately one-third of children with this condition have delays in developing physical skills such as sitting, crawling, or walking. The average IQ of affected individuals is about 26 points lower than that of their parents without the duplication. About 80 percent of people with a 16p11.2 duplication have problems related to speech or language. Both expressive language skills (vocabulary and the production of speech) and receptive language skills (the ability to understand speech) can be affected.

One of the most common behavioral problems associated with this chromosomal change is attention deficit hyperactivity disorder. Autism spectrum disorders, which affect communication and social skills, are diagnosed in about one in five people with a 16p11.2 duplication. Affected individuals also have an increased risk of mental health problems, including schizophrenia, anxiety, and depression. Recurrent seizures are possible in this condition, although they do not occur in most affected individuals.

Other abnormalities that can occur with a 16p11.2 duplication include malformations of the kidneys and urinary tract. However, there is no particular pattern of physical abnormalities that characterizes 16p11.2 duplications; signs and symptoms related to the chromosomal change vary even among affected members of the same family.

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Proximal 16p11.2 microduplication syndrome is a rare chromosomal anomaly syndrome resulting from a partial duplication of the short arm of chromosome 16 characterized by developmental delay and intellectual disability of a highly variable degree, autism spectrum, obsessive-compulsive, attention deficit hyperactivity disorder, speech articulation abnormalities, muscular hypotonia, tremor, hyper- or hyporeflexia, seizures, microcephaly, neuroimaging abnormalities, decreased body mass index and schizophrenia or bipolar disorder later on in life.

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Medical Term Other Names Description
Seizures Epilepsy Seizures are an intermittent abnormality of the central nervous system due to a sudden, excessive, disorderly discharge of cerebral neurons and characterized clinically by some combination of disturbance of sensation, loss of consciousness, impairment of psychic function, or convulsive movements. The term epilepsy is used to describe chronic, recurrent seizures.
Autism Autism is a neurodevelopmental disorder characterized by impaired social interaction and communication, and by restricted and repetitive behavior. Autism begins in childhood. It is marked by the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interest. Manifestations of the disorder vary greatly depending on the developmental level and chronological age of the individual (DSM-IV).
Muscular hypotonia Muscle hypotonia, Low or weak muscle tone Muscular hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle), often involving reduced muscle strength. Hypotonia is characterized by a diminished resistance to passive stretching.
Attention deficit hyperactivity disorder Attention deficits, Attention deficit disorder, Childhood attention deficit/hyperactivity disorder, Attention deficit [more] Attention deficit hyperactivity disorder (ADHD) manifests at age 2-3 years or by first grade at the latest. The main symptoms are distractibility, impulsivity, hyperactivity, and often trouble organizing tasks and projects, difficulty going to sleep, and social problems from being aggressive, loud, or impatient.
Anxiety Anxiousness, Excessive, persistent worry and fear [more] Intense feelings of nervousness, tenseness, or panic, often in reaction to interpersonal stresses; worry about the negative effects of past unpleasant experiences and future negative possibilities; feeling fearful, apprehensive, or threatened by uncertainty; fears of falling apart or losing control.
Microcephaly small cranium, Decreased circumference of cranium, Small head, Small skull, Small head circumference, Reduced head circumference, Decreased size of cranium, Decreased size of skull, Abnormally small skull, Decreased size of head, Abnormally small cranium, small calvarium, Abnormally small head [more] Occipito-frontal (head) circumference (OFC) less than -3 standard deviations compared to appropriate, age matched, normal standards (Ross JJ, Frias JL 1977, PMID:9683597). Alternatively, decreased size of the cranium.
Hyperactivity Hyperactive behavior
Tremor An unintentional, oscillating to-and-fro muscle movement about a joint axis.
Upper limb undergrowth Hypoplasia involving bones of the upper limbs, Shortening of the arms, Short arms [more] Arm shortening because of underdevelopment of one or more bones of the upper extremity.
Generalized hypotonia Generalized muscular hypotonia, Decreased muscle tone, Low muscle tone, Hypotonia [more] Generalized muscular hypotonia (abnormally low muscle tone).
Autistic behavior Autistic behaviour, Pervasive developmental disorder, Autism spectrum disorder, Autism spectrum disorders [more] A disorder beginning in childhood. It is marked by the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interest. Manifestations of the disorder vary greatly depending on the developmental level and chronological age of the individual (DSM-IV).
Hyporeflexia Decreased deep tendon reflexes, Diminished deep tendon reflexes, Decreased tendon reflexes, Depressed tendon reflexes [more] Reduction of neurologic reflexes such as the knee-jerk reaction.
Bipolar affective disorder Bipolar disorder
Decreased body mass index Decreased BMI Abnormally decreased weight-to-height squared ratio, calculated by dividing the individual's weight in kilograms by the square of the individual's height in meters and used as an indicator of underweight compared to averages.
Behavioral abnormality Psychiatric disturbances, Behavioral problems, Behavioral/psychiatric abnormalities, Behavioural/Psychiatric abnormality [more] An abnormality of mental functioning including various affective, behavioural, cognitive and perceptual abnormalities.
Schizophrenia A mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social or occupational dysfunction. The onset of symptoms typically occurs in young adulthood, with a global lifetime prevalence of about 0.3-0.7%.
Global developmental delay Psychomotor developmental delay, Psychomotor retardation, Developmental delay, Lack of psychomotor development, Cognitive delay, Delayed intellectual development, Delayed milestones, Psychomotor development deficiency, Developmental retardation, Motor and developmental delay, Developmental delay in early childhood, Retarded psychomotor development, Retarded mental development, Delayed cognitive development, Retarded development, Delayed developmental milestones, Delayed development, Psychomotor development failure, Mental and motor retardation, Psychomotor delay, Delayed psychomotor development [more] A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
Depressivity Depression, Depressive disorder Frequent feelings of being down, miserable, and/or hopeless; difficulty recovering from such moods; pessimism about the future; pervasive shame; feeling of inferior self-worth; thoughts of suicide and suicidal behavior.
Intellectual disability Nonprogressive intellectual disability, Poor school performance, Mental-retardation, Dull intelligence, Nonprogressive mental retardation, Mental deficiency, Mental retardation, nonspecific, Low intelligence [more] Subnormal intellectual functioning which originates during the developmental period. Intellectual disability, previously referred to as mental retardation, has been defined as an IQ score below 70.

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