LIG4 syndrome

What it is

From: Orphanet

LIG4 syndrome is a hereditary disorder associated with impaired DNA double-strand break repair mechanisms and characterized by microcephaly, unusual facial features, growth and developmental delay, skin anomalies, and pancytopenia, which is associated with combined immunodeficiency (CID).

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.

Abnormality of chromosome stability · Very frequent (99-80%)

A type of chromosomal aberration characterized by reduced resistance of chromosomes to change or deterioration.

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.

Growth delay · Very frequent (99-80%)

A deficiency or slowing down of growth pre- and postnatally.

Immunodeficiency · Very frequent (99-80%)

Failure of the immune system to protect the body adequately from infection, due to the absence or insufficiency of some component process or substance.

Microcephaly · Very frequent (99-80%)

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

Bird-like facies · Very frequent (99-80%)

Abnormality of bone marrow cell morphology · Frequent (79-30%)

An anomaly of the form or number of cells in the bone marrow.

Acute leukemia · Frequent (79-30%)

A clonal (malignant) hematopoietic disorder with an acute onset, affecting the bone marrow and the peripheral blood. The malignant cells show minimal differentiation and are called blasts, either myeloid blasts (myeloblasts) or lymphoid blasts (lymphoblasts).

Biparietal narrowing · Frequent (79-30%)

A narrowing of the biparietal diameter (i.e., of the transverse distance between the protuberances of the two parietal bones of the skull).

Brachycephaly · Frequent (79-30%)

An abnormality of skull shape characterized by a decreased anterior-posterior diameter. That is, a cephalic index greater than 81%. Alternatively, an apparently shortened anteroposterior dimension (length) of the head compared to width.

Convex nasal ridge · Frequent (79-30%)

Nasal ridge curving anteriorly to an imaginary line that connects the nasal root and tip. The nose appears often also prominent, and the columella low.

Cutaneous photosensitivity · Frequent (79-30%)

An increased sensitivity of the skin to light. Photosensitivity may result in a rash upon exposure to the sun (which is known as photodermatosis). Photosensitivity can be diagnosed by phototests in which light is shone on small areas of skin.

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.

Erythema · Frequent (79-30%)

Redness of the skin, caused by hyperemia of the capillaries in the lower layers of the skin.

Other findings in the same source

From: Orphanet

Additional reported features include Intellectual disability (Frequent (79-30%)); Low anterior hairline (Frequent (79-30%)); Lymphoma (Frequent (79-30%)); Micrognathia (Frequent (79-30%)); Pancytopenia (Frequent (79-30%)); Severe combined immunodeficiency (Frequent (79-30%)); Telecanthus (Frequent (79-30%)); Thin vermilion border (Frequent (79-30%)); Upslanted palpebral fissure (Frequent (79-30%)); Wide nasal bridge (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 recessive

Frequency and the population described

From: Orphanet

Reported case(s): 28.0; 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 recessive pattern usually involves disease-causing changes in both copies of a gene. Parents may each carry one altered copy without having the condition themselves. A genetic counsellor can explain carrier testing and reproductive implications using the actual laboratory findings, rather than the condition name alone.

Which doctor should you see?

The suggested department for discussing LIG4 syndrome is Allergy and Immunology, with a allergist / clinical immunologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

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

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 history suggest an allergy, an immune problem or another explanation?
• How would any proposed allergy or immune test change care?
• Is an individual emergency plan needed, and who should understand it?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for LIG4 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.