PURA syndrome

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

PURA syndrome is a condition characterized by intellectual disability and delayed development of speech and motor skills, such as walking. Expressive language skills (vocabulary and the production of speech) are generally more severely affected than receptive language skills (the ability to understand speech), and most affected individuals are unable to speak. People with PURA syndrome may learn to walk later than their peers; many are never able to walk. In infancy, affected infants have very weak muscle tone (hypotonia) and feeding difficulties. Problems with swallowing (dysphagia) can last throughout life. In addition, affected infants can be excessively sleepy (hypersomnolent), have a low body temperature (hypothermia), and have short pauses in breathing (apnea) or episodes of abnormally slow breathing (hypoventilation). These breathing problems usually go away after age 1.

Recurrent seizures (epilepsy) are also common in PURA syndrome. Seizures usually begin before age 5 with uncontrolled muscle jerks (myoclonus). Other types of seizures can develop, such as generalized tonic-clonic seizures, which involve loss of consciousness, muscle rigidity, and convulsions. In people with PURA syndrome, seizures are often difficult to control.

Other features in people with PURA syndrome can include abnormalities of the heart, eyes, urogenital tract, gastrointestinal tract, and skeleton. Some affected individuals have symptoms of a hormonal problem, such as early sexual development (precocious puberty) or low levels of vitamin D (which is a hormone).

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

PURA syndrome is caused by mutations in the PURA gene, which provides instructions for making a protein called Pur-alpha (Purα). This protein has multiple roles in cells, including controlling the activity of genes (gene transcription) and aiding in the copying (replication) of DNA. The Purα protein is especially important for normal brain development. Purα helps direct the growth and division of nerve cells (neurons). It may also be involved in the formation or maturation of myelin, the protective substance that covers nerves and promotes the efficient transmission of nerve impulses.

Mutations in the PURA gene are thought to lead to a reduced amount of functional Purα protein. Although it is not understood how a partial loss of Purα function leads to the signs and symptoms of PURA syndrome, researchers suspect that it may alter normal brain development and impair the function of neurons, leading to developmental problems and seizures in people with the condition.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.

Most cases of this condition result from new (de novo) mutations in the gene that occur during the formation of reproductive cells (eggs or sperm) in an affected individual’s parent or in early embryonic development. These cases occur in people with no history of the disorder in their family.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

PURA syndrome is a rare condition affecting at least 70 individuals. It is estimated to account for fewer than 1 percent of cases of developmental delay.

Understanding terms used in the source

These definitions explain medical words used above. A definition is not evidence that another condition is present, and it does not predict how a symptom will develop. Ask the clinician which terms apply to the actual examination or test result.

Intellectual disability

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.

Loss of consciousness

Loss of awareness of oneself or one's surroundings, involving (i) a loss of normal motor control is evident as flaccidity or stiffness, either of which can be accompanied by jerking movements, and postural control is lost so that patients fall if they are in an upright position; (ii) normal responsiveness is lost; and (iii) the patient experiences amnesia for the event. Loss of consciousness my be transitory (e.g., syncope) or prolonged.

Feeding difficulties

Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it.

Precocious puberty

The onset of secondary sexual characteristics before a normal age. Although it is difficult to define normal age ranges because of the marked variation with which puberty begins in normal children, precocious puberty can be defined as the onset of puberty before the age of 8 years in girls or 9 years in boys.

Hypoventilation

A reduction in the amount of air transported into the pulmonary alveoli by breathing, leading to hypercapnia (increase in the partial pressure of carbon dioxide).

Which doctor should you see?

The suggested department for discussing PURA 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 PURA 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.