Monosomy 13q14 syndrome

What it is

From: Orphanet

Monosomy 13q14 is a rare chromosomal anomaly syndrome, resulting from a partial deletion of the long arm of chromosome 13, characterized by developmental delay, variable degrees of intellectual disability, retinoblastoma and craniofacial dysmorphism (incl. micro/dolichocephaly, high and broad forehead, prominent eyebrows, thick, anteverted ear lobes, short nose with a broad nasal bridge and bulbous tip, prominent philtrum, large mouth with thin upper lip and thick, everted lower lip). Other features reported include high birth weight, macrocephaly, pinealoma, hepatomegaly, inguinal hernia and cryptorchidism.

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.

Hypertelorism · Very frequent (99-80%)

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

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.

Intrauterine growth retardation · Very frequent (99-80%)

An abnormal restriction of fetal growth with fetal weight below the tenth percentile for gestational age.

Microcephaly · Very frequent (99-80%)

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

Prominent nasal bridge · Very frequent (99-80%)

Anterior positioning of the nasal root in comparison to the usual positioning for age.

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).

Thickened helices · Very frequent (99-80%)

Increased thickness of the helix of the ear.

Wide nasal bridge · Very frequent (99-80%)

Increased breadth of the nasal bridge (and with it, the nasal root).

Abnormal cardiovascular system morphology · Frequent (79-30%)

Any structural anomaly of the heart and blood vessels.

Abnormal dermatoglyphics · Frequent (79-30%)

An abnormality of dermatoglyphs (fingerprints), which are present on fingers, palms, toes, and soles.

Brachydactyly · Frequent (79-30%)

Digits that appear disproportionately short compared to the hand/foot. The word brachydactyly is used here to describe a series distinct patterns of shortened digits (brachydactyly types A-E). This is the sense used here.

Cataract · Frequent (79-30%)

A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule.

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.

Other findings in the same source

From: Orphanet

Additional reported features include Finger syndactyly (Frequent (79-30%)); Hypotonia (Frequent (79-30%)); Iris coloboma (Frequent (79-30%)); Low-set ears (Frequent (79-30%)); Micrognathia (Frequent (79-30%)); Microphthalmia (Frequent (79-30%)); Protruding ear (Frequent (79-30%)); Ptosis (Frequent (79-30%)); Retinoblastoma (Frequent (79-30%)); Short neck (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

Not applicable

Frequency and the population described

From: Orphanet

Prevalence at birth: Unknown; Worldwide; Class only. Point prevalence: Unknown; Worldwide; Class only.

Which doctor should you see?

The suggested department for discussing Monosomy 13q14 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 Monosomy 13q14 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.