8q24.3 microdeletion syndrome

What it is

From: Orphanet

A multiple congenital anomalies/dysmorphic - intellectual disability syndrome characterized by feeding problems, growth retardation, microcephaly, developmental delay, digital and vertebral anomalies, joint laxity/dislocation, cardiac and renal defects, and dysmorphic facial features (including plagiocephaly, prominent forehead, bitemporal narrowing, bilateral coloboma, epicanthal folds, malformations of the outer and middle ear, wide nasal bridge, anteverted nares, prominent and bulbous nose tip, long philtrum, thin lips, high and narrow palate, micrognathia with prognathism/retrognathism, full cheeks, and short, broad neck). Additional variable manifestations include obstructive apneas, recurrent pneumonia, 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.

Global developmental delay · Very frequent (99-80%)

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.

Intellectual disability, moderate · Very frequent (99-80%)

Moderate intellectual disability (ID) is defined as a type of ID characterized by moderately sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) the range of 35-49.

Short stature · Very frequent (99-80%)

A height below that which is expected according to age and gender norms. Although there is no universally accepted definition of short stature, many refer to "short stature" as height more than 2 standard deviations below the mean for age and gender (or below the 3rd percentile for age and gender dependent norms).

Abnormal heart morphology · Frequent (79-30%)

Any structural anomaly of the heart.

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

An abnormality affecting one or both hands.

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).

Asymmetry of the ears · Frequent (79-30%)

An asymmetriy, i.e., difference in size, shape or position between the left and right ear.

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.

Broad nasal tip · Frequent (79-30%)

Increase in width of the nasal tip.

Clinodactyly of the 5th finger · Frequent (79-30%)

Clinodactyly refers to a bending or curvature of the fifth finger in the radial direction (i.e., towards the 4th finger).

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.

Expressive language delay · Frequent (79-30%)

A delay in the acquisition of the ability to use language to communicate needs, wishes, or thoughts.

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.

Full cheeks · Frequent (79-30%)

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

Other findings in the same source

From: Orphanet

Additional reported features include Intrauterine growth retardation (Frequent (79-30%)); Joint hypermobility (Frequent (79-30%)); Long philtrum (Frequent (79-30%)); Nasogastric tube feeding in infancy (Frequent (79-30%)); Pes valgus (Frequent (79-30%)); Posteriorly rotated ears (Frequent (79-30%)); Short middle phalanx of the 5th finger (Frequent (79-30%)); Short neck (Frequent (79-30%)); Smooth philtrum (Frequent (79-30%)); Square face (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Antenatal; Neonatal

Inheritance in the source

From: Orphanet

Not applicable

Frequency and the population described

From: Orphanet

Reported case(s): 2.0; Worldwide. This is a published case count, not prevalence. Point prevalence: <1 / 1 000 000; Worldwide; Class only.

Which doctor should you see?

The suggested department for discussing 8q24.3 microdeletion syndrome 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 8q24.3 microdeletion 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.