Intellectual disability-seizures-abnormal gait-facial dysmorphism syndrome

What it is

From: Orphanet

A rare genetic multiple congenital anomalies/dysmorphic syndrome characterized by global developmental delay, intellectual disability, seizures, abnormal gait, and craniofacial dysmorphism (including coarse features, depressed nasal bridge, anteverted nares, broad nasal tip, prominent maxilla and upper lip, wide mouth, abnormal gingiva, and widely spaced teeth). Additional reported manifestations are ocular anomalies, cardiac defects, gastrointestinal problems, and autistic features. Brain imaging may show thin corpus callosum, white matter abnormalities, or dilated ventricles.

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.

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.

Everted upper lip vermilion · Very frequent (99-80%)

Inner aspect of the upper lip vermilion (normally apposing the teeth) visible in a frontal view, i.e., the presence of an everted upper lip.

Full cheeks · Very frequent (99-80%)

Increased prominence or roundness of soft tissues between zygomata and mandible.

Hyperplasia of the maxilla · Very frequent (99-80%)

Abnormally increased dimension of the maxilla, especially relative to the mandible, resulting in a malocclusion or malalignment between the upper and lower teeth or in anterior positioning of the nasal base, increased convexity of the face, increased nasolabial angle, or increased width (transverse dimension of the maxilla.

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.

Seizure · Very frequent (99-80%)

A seizure is an intermittent abnormality of nervous system physiology characterized by a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.

Widely spaced teeth · Very frequent (99-80%)

Increased spaces (diastemata) between most of the teeth in the same dental arch.

Abnormality of the gingiva · Frequent (79-30%)

Any abnormality of the gingiva (also known as gums).

Absent cupid's bow · Frequent (79-30%)

Lack of paramedian peaks and median notch of the upper lip vermilion.

Anteverted nares · Frequent (79-30%)

Anteriorly-facing nostrils viewed with the head in the Frankfurt horizontal and the eyes of the observer level with the eyes of the subject. This gives the appearance of an upturned nose (upturned nasal tip).

Bilateral tonic-clonic seizure · Frequent (79-30%)

A bilateral tonic-clonic seizure is a seizure defined by a tonic (bilateral increased tone, lasting seconds to minutes) and then a clonic (bilateral sustained rhythmic jerking) phase.

Brain imaging abnormality · Frequent (79-30%)

An anomaly of metabolism or structure of the brain identified by imaging.

Coarse facial features · Frequent (79-30%)

Absence of fine and sharp appearance of brows, nose, lips, mouth, and chin, usually because of rounded and heavy features or thickened skin with or without thickening of subcutaneous and bony tissues.

Delayed ability to sit · Frequent (79-30%)

A failure to achieve the ability to sit at an appropriate developmental stage. Most children sit with support at 6 months of age and sit steadily without support at 9 months of age.

Other findings in the same source

From: Orphanet

Additional reported features include Delayed ability to walk (Frequent (79-30%)); Depressed nasal bridge (Frequent (79-30%)); Failure to thrive (Frequent (79-30%)); Feeding difficulties in infancy (Frequent (79-30%)); Generalized non-motor (absence) seizure (Frequent (79-30%)); Hypotonia (Frequent (79-30%)); Increased axial length of the globe (Frequent (79-30%)); Micrognathia (Frequent (79-30%)); Mild global developmental delay (Frequent (79-30%)); Severe global developmental delay (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Infancy

Inheritance in the source

From: Orphanet

Autosomal dominant

Frequency and the population described

From: Orphanet

Reported case(s): 15.0; 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 Intellectual disability-seizures-abnormal gait-facial dysmorphism syndrome is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with clinical geneticist referral.

Additional services that may be relevant, depending on the findings, include: Neurology.

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 Intellectual disability-seizures-abnormal gait-facial dysmorphism syndrome. 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.