MedGen

Autism spectrum disorder (ASD) is a condition that appears very early in childhood development, varies in severity, and is characterized by impaired social skills, communication problems, and repetitive actions. These difficulties can interfere with affected individuals' ability to function in social, academic, and employment settings. People with ASD also have an increased risk of psychiatric problems such as anxiety, depression, obsessive-compulsive disorder, and eating disorders.

From as early as 1 to 2 years of age, people with ASD have an impaired ability to interact with other people; they are often more comfortable dealing with objects. Affected individuals have difficulty understanding and using non-verbal social cues such as eye contact, facial expressions, gestures, and body language. Inability to recognize and use these cues makes it hard for affected individuals to understand the feelings of others or communicate their own feelings appropriately. Signs of ASD, such as reduced eye contact and social interaction, can sometimes be detected before age 2. However, the condition is usually diagnosed between ages 2 and 4, when more advanced communication and social skills, such as learning to play with others, typically begin to develop.

Repetitive actions in ASD can include simple actions such as rocking, hand-flapping, or repetition of words or noises (echolalia). Affected individuals often dwell on or repeatedly express particular thoughts; this trait is called perseveration. People with ASD tend to be rigid about their established routines and may strongly resist disruptions such as changes in schedule. They may also have difficulty tolerating sensory stimuli such as loud noises or bright lights.

While social and communication difficulties and unusual actions define ASD, affected individuals can have a wide range of intellectual abilities and language skills. A majority of people with ASD have mild to moderate intellectual disability, while others have average to above-average intelligence. Some have particular cognitive abilities that greatly surpass their overall level of functioning, often in areas such as music, mathematics, or memory.

Some people with ASD do not speak at all, while others use language fluently. However, fluent speakers with ASD often have problems associated with verbal communication. They might speak in a monotone voice, have unusual vocal mannerisms, or choose unusual topics of conversation.

Several diagnoses that used to be classified as separate conditions are now grouped together under the diagnosis of ASD. For example, autistic disorder was a term that was used when affected individuals had limited or absent verbal communication, often in combination with intellectual disability. By contrast, Asperger syndrome was a diagnosis formerly applied to affected individuals of average or above-average intelligence who were not delayed in their language development. The broader diagnosis of ASD was established because many affected individuals fall outside of the strict definitions of the narrower diagnoses, and their intellectual and communication abilities may change over time. However, some individuals who were previously diagnosed with one of the subtypes now do not meet all the criteria of the new umbrella diagnosis. [from MedlinePlus Genetics]

A category of developmental disorders characterized by impaired communication and socialization skills. The impairments are incongruent with the individual''s developmental level or mental age. These disorders can be associated with general medical or genetic conditions. [from NCI]

Present in 0% of the cases. [from HPO]

Atrial septal defect (ASD) is a congenital abnormality of the interatrial septum that enables blood flow between the left and right atria via the interatrial septum. [from HPO]

Persistent deficits in social interaction and communication and interaction as well as a markedly restricted repertoire of activity and interest as well as repetitive patterns of behavior. [from HPO]

A degree of language development that is significantly below the norm for a child of a specified age. [from HPO]

Autism, the prototypic pervasive developmental disorder (PDD), is usually apparent by 3 years of age. It is characterized by a triad of limited or absent verbal communication, a lack of reciprocal social interaction or responsiveness, and restricted, stereotypic, and ritualized patterns of interests and behavior (Bailey et al., 1996; Risch et al., 1999). 'Autism spectrum disorder,' sometimes referred to as ASD, is a broader phenotype encompassing the less severe disorders Asperger syndrome (see ASPG1; 608638) and pervasive developmental disorder, not otherwise specified (PDD-NOS). 'Broad autism phenotype' includes individuals with some symptoms of autism, but who do not meet the full criteria for autism or other disorders. Mental retardation coexists in approximately two-thirds of individuals with ASD, except for Asperger syndrome, in which mental retardation is conspicuously absent (Jones et al., 2008). Genetic studies in autism often include family members with these less stringent diagnoses (Schellenberg et al., 2006). Levy et al. (2009) provided a general review of autism and autism spectrum disorder, including epidemiology, characteristics of the disorder, diagnosis, neurobiologic hypotheses for the etiology, genetics, and treatment options. Genetic Heterogeneity of Autism Autism is considered to be a complex multifactorial disorder involving many genes. Accordingly, several loci have been identified, some or all of which may contribute to the phenotype. Included in this entry is AUTS1, which has been mapped to chromosome 7q22. Other susceptibility loci include AUTS3 (608049), which maps to chromosome 13q14; AUTS4 (608636), which maps to chromosome 15q11; AUTS6 (609378), which maps to chromosome 17q11; AUTS7 (610676), which maps to chromosome 17q21; AUTS8 (607373), which maps to chromosome 3q25-q27; AUTS9 (611015), which maps to chromosome 7q31; AUTS10 (611016), which maps to chromosome 7q36; AUTS11 (610836), which maps to chromosome 1q41; AUTS12 (610838), which maps to chromosome 21p13-q11; AUTS13 (610908), which maps to chromosome 12q14; AUTS14A (611913), which has been found in patients with a deletion of a region of 16p11.2; AUTS14B (614671), which has been found in patients with a duplication of a region of 16p11.2; AUTS15 (612100), associated with mutation in the CNTNAP2 gene (604569) on chromosome 7q35-q36; AUTS16 (613410), associated with mutation in the SLC9A9 gene (608396) on chromosome 3q24; AUTS17 (613436), associated with mutation in the SHANK2 gene (603290) on chromosome 11q13; AUTS18 (615032), associated with mutation in the CHD8 gene (610528) on chromosome 14q11; AUTS19 (615091), associated with mutation in the EIF4E gene (133440) on chromosome 4q23; and AUTS20 (618830), associated with mutation in the NLGN1 gene (600568) on chromosome 3q26. (NOTE: the symbol 'AUTS2' has been used to refer to a gene on chromosome 7q11 (KIAA0442; 607270) and therefore is not used as a part of this autism locus series.) There are several X-linked forms of autism susceptibility: AUTSX1 (300425), associated with mutations in the NLGN3 gene (300336); AUTSX2 (300495), associated with mutations in NLGN4 (300427); AUTSX3 (300496), associated with mutations in MECP2 (300005); AUTSX4 (300830), associated with variation in the region on chromosome Xp22.11 containing the PTCHD1 gene (300828); AUTSX5 (300847), associated with mutations in the RPL10 gene (312173); and AUTSX6 (300872), associated with mutation in the TMLHE gene (300777). A locus on chromosome 2q (606053) associated with a phenotype including intellectual disability and speech deficits was formerly designated AUTS5. Folstein and Rosen-Sheidley (2001) reviewed the genetics of autism. [from OMIM]

Neurodevelopmental disorder is a behavioral and cognitive disorder with onset during the developmental period that involves impaired or aberrant development of intellectual, motor, or social functions. [from SNOMEDCT_US]

Primary lymphedema is caused by anatomic or functional defects in the lymphatic system, resulting in chronic swelling of body parts and lymphatic-system malformation. [from MONDO]

Any abnormality of the cardiovascular system. [from HPO]

A group of signs, symptoms, and clinicopathological characteristics that may or may not have a genetic basis and collectively define an abnormal condition. [from NCI]

The presence of multiple congenital malformations in a patient. [from NCI]

A condition caused by a deficiency of parathyroid hormone characterized by hypocalcemia and hyperphosphatemia. [from HPO]

Any structural anomaly of the heart. [from HPO]

A disorder with homogeneous therapeutic possibilities and an identified pathophysiological mechanism. Developmental anomalies are excluded. [from ORDO]

Individuals with 22q11.2 deletion syndrome (22q11.2DS) can present with a wide range of features that are highly variable, even within families. The major clinical manifestations of 22q11.2DS include congenital heart disease, particularly conotruncal malformations (ventricular septal defect, tetralogy of Fallot, interrupted aortic arch, and truncus arteriosus), palatal abnormalities (velopharyngeal incompetence, submucosal cleft palate, bifid uvula, and cleft palate), immune deficiency, characteristic facial features, and learning difficulties. Hearing loss can be sensorineural and/or conductive. Laryngotracheoesophageal, gastrointestinal, ophthalmologic, central nervous system, skeletal, and genitourinary anomalies also occur. Psychiatric illness and autoimmune disorders are more common in individuals with 22q11.2DS. [from GeneReviews]

A disorder that results from a chromosomal abnormality. [from NCI]

A disorder diagnosed in childhood that is marked by either physical or mental impairment or both, which in turn affects the child from achieving age related developmental milestones. [from NCI]

22q11.2 duplication is a condition caused by an extra copy of a small piece of chromosome 22. The duplication occurs near the middle of the chromosome at a location designated q11.2.

The features of this condition vary widely, even among members of the same family. Affected individuals may have developmental delay, intellectual disability, slow growth leading to short stature, and weak muscle tone (hypotonia). Many people with the duplication have no apparent physical or intellectual disabilities. [from MedlinePlus Genetics]

Neurodevelopmental-craniofacial syndrome with variable renal and cardiac abnormalities (NECRC) is an autosomal dominant disorder characterized by dysmorphic craniofacial features associated with mild developmental delay, mildly impaired intellectual development or learning difficulties, speech delay, and behavioral abnormalities. About half of patients have congenital anomalies of the kidney and urinary tract (CAKUT) and/or congenital cardiac defects, including septal defects (Connaughton et al., 2020). [from OMIM]