Autism spectrum disorder due to AUTS2 deficiency

What it is

From: Orphanet

A rare genetic syndromic intellectual disability characterized by global developmental delay and borderline to severe intellectual disability, autism spectrum disorder with obsessive behavior, stereotypies, hyperactivity but frequently friendly and affable personality, feeding difficulties, short stature, muscular hypotonia, microcephaly, characteristic dysmorphic features (hypertelorism, high arched eyebrows, ptosis, deep and/or broad nasal bridge, broad/prominent nasal tip, short and/or upturned philtrum, narrow mouth, and micrognathia), and skeletal anomalies (kyphosis and/or scoliosis, arthrogryposis, slender habitus and extremities). Other clinical features may include hernias, congenital heart defects, cryptorchidism and seizures.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Abnormal facial shape · Very frequent (99-80%)

An abnormal morphology (form) of the face or its components.

Delayed speech and language development · Very frequent (99-80%)

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

Intellectual disability · Very frequent (99-80%)

The term intellectual disability or intellectual developmental disorder is used to describe significantly sub-average intellectual and adaptive functioning based on clinical assessment and as measured by individually administered, appropriately normed, standardized and validated tests of intellectual functioning and adaptive behavior, with onset during the developmental period from infancy through adolescence.

Abnormal repetitive mannerisms · Frequent (79-30%)

Use of the same abnormal action in response to certain triggers or at random. They may be used as a way to regulate one's internal state but must otherwise have no apparent functional purpose.

Autistic behavior · Frequent (79-30%)

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.

Compulsive behaviors · Frequent (79-30%)

Behavior that consists of repetitive acts, characterized by the feeling that one "has to" perform them, while being aware that these acts are not in line with one's overall goal.

Epicanthus · Frequent (79-30%)

A fold of skin starting above the medial aspect of the upper eyelid and arching downward to cover, pass in front of and lateral to the medial canthus.

Feeding difficulties in infancy · Frequent (79-30%)

Impaired feeding performance of an infant as manifested by difficulties such as weak and ineffective sucking, brief bursts of sucking, and falling asleep during sucking. There may be difficulties with chewing or maintaining attention.

Generalized hypotonia · Frequent (79-30%)

Generalized muscular hypotonia (abnormally low muscle tone).

Global developmental delay · Frequent (79-30%)

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.

Highly arched eyebrow · Frequent (79-30%)

Increased height of the central portion of the eyebrow, forming a crescent, semicircular, or inverted U shape.

Hypertelorism · Frequent (79-30%)

Interpupillary distance more than 2 SD above the mean (alternatively, the appearance of an increased interpupillary distance or widely spaced eyes).

Low-set ears · Frequent (79-30%)

Upper insertion of the ear to the scalp below an imaginary horizontal line drawn between the inner canthi of the eye and extending posteriorly to the ear.

Microcephaly · Frequent (79-30%)

Head circumference below 2 standard deviations below the mean for age and gender.

Other findings in the same source

From: Orphanet

Additional reported features include Micrognathia (Frequent (79-30%)); Narrow mouth (Frequent (79-30%)); Proptosis (Frequent (79-30%)); Short palpebral fissure (Frequent (79-30%)); Short philtrum (Frequent (79-30%)); Short stature (Frequent (79-30%)); Small for gestational age (Frequent (79-30%)); Sound sensitivity (Frequent (79-30%)); Specific learning disability (Frequent (79-30%)); Strabismus (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Infancy; Neonatal

Inheritance in the source

From: Orphanet

Autosomal dominant

Frequency and the population described

From: Orphanet

Reported case(s): 60.0; Worldwide. This is a published case count, not prevalence. Point prevalence: <1 / 1 000 000; Worldwide; Class only.

Understanding the inheritance label

From: MedlinePlus Genetics

An autosomal dominant pattern means that one altered copy of a relevant gene can be sufficient for the condition. Some affected people inherit the change; others have a new change without an affected parent. The precise finding, family history and condition determine what this means for relatives.

Which doctor should you see?

The suggested department for discussing Autism spectrum disorder due to AUTS2 deficiency is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with clinical geneticist referral.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Does the exact genetic or chromosome finding explain the observed features?
• Would a genetic counsellor help the family understand the result?
• Which organ-specific assessments are appropriate for this particular diagnosis?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Autism spectrum disorder due to AUTS2 deficiency. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.