CHOPS syndrome

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

CHOPS syndrome is a disorder involving multiple abnormalities that are present from birth (congenital). The name "CHOPS" is an abbreviation for a list of features of the disorder including cognitive impairment, coarse facial features, heart defects, obesity, lung (pulmonary) involvement, short stature, and skeletal abnormalities.

Children with CHOPS syndrome have intellectual disability and delayed development of skills such as sitting and walking. Characteristic facial features include a round face; thick hair; thick eyebrows that grow together in the middle (synophrys); wide-set, bulging eyes with long eyelashes; a short nose; and down-turned corners of the mouth.

Most affected individuals are born with a heart defect called patent ductus arteriosus (PDA). The ductus arteriosus is a connection between two major arteries, the aorta and the pulmonary artery. This connection is open during fetal development and normally closes shortly after birth. However, the ductus arteriosus remains open, or patent, in babies with PDA. If untreated, this heart defect causes infants to breathe rapidly, feed poorly, and gain weight slowly; in severe cases, it can lead to heart failure. Multiple heart abnormalities have sometimes been found in children with CHOPS syndrome. In addition to PDA, affected individuals may have ventricular septal defect, which is a defect in the muscular wall (septum) that separates the right and left sides of the heart's lower chamber.

People with CHOPS syndrome have abnormalities of the throat and airways that cause momentary cessation of breathing while asleep (obstructive sleep apnea). These abnormalities can also cause affected individuals to breathe food or fluids into the lungs accidentally, which can lead to a potentially life-threatening bacterial lung infection (aspiration pneumonia) and chronic lung disease. Affected individuals are shorter than more than 97 percent of their peers and are overweight for their height. They also have skeletal differences including unusually short fingers and toes (brachydactyly) and abnormally-shaped spinal bones (vertebrae).

Other features that can occur in CHOPS syndrome include a small head size (microcephaly); hearing loss; clouding of the lens of the eye (cataract); a single, horseshoe-shaped kidney; and, in affected males, undescended testes (cryptorchidism).

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

CHOPS syndrome is caused by mutations in the AFF4 gene. This gene provides instructions for making part of a protein complex called the super elongation complex (SEC). During embryonic development, the SEC is involved in an activity called transcription, which is the first step in the production of proteins from genes. By re-starting the transcription of certain genes after pauses that normally occur during the process, the SEC helps ensure that development proceeds appropriately before birth.

Mutations in the AFF4 gene are thought to result in an AFF4 protein that is not broken down when it is no longer needed, so more AFF4 protein is available than usual. The excess AFF4 protein interferes with normal pauses in transcription. This dysregulation of transcription leads to problems in the development of multiple organs and tissues, resulting in the signs and symptoms of CHOPS syndrome.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

CHOPS syndrome is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. All known cases of this condition result from new (de novo) mutations in the gene that occur during the formation of reproductive cells (eggs or sperm) or in early embryonic development. Affected individuals have no history of the disorder in their family.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

CHOPS syndrome is a rare disorder whose prevalence is unknown. Only a few affected individuals have been described in the medical literature.

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 skeletal morphology · Very frequent (99-80%)

An abnormality of the form, structure, or size of the skeletal system.

Abnormality of the respiratory system · Very frequent (99-80%)

An abnormality of the respiratory system, which include the airways, lungs, and the respiratory muscles.

Anteverted nares · Very frequent (99-80%)

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).

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.

Highly arched eyebrow · Very frequent (99-80%)

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

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.

Long eyelashes · Very frequent (99-80%)

Mid upper eyelash length >10 mm or increased length of the eyelashes (subjective).

Obesity · Very frequent (99-80%)

Accumulation of substantial excess body fat.

Other findings in the same source

From: Orphanet

Additional reported features include Short stature (Very frequent (99-80%)); Synophrys (Very frequent (99-80%)); Abnormal heart morphology (Frequent (79-30%)); Abnormal vertebral morphology (Frequent (79-30%)); Aspiration pneumonia (Frequent (79-30%)); Brachydactyly (Frequent (79-30%)); Chronic lung disease (Frequent (79-30%)); Constipation (Frequent (79-30%)); Gastroesophageal reflux (Frequent (79-30%)); Gastrostomy tube feeding in infancy (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing CHOPS 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

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

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.