Citrullinemia type II

What it is

From: Orphanet

A severe subtype of citrin deficiency characterized clinically by adult onset (20 and 50 years of age), recurrent episodes of hyperammonemia and associated neuropsychiatric symptoms such as nocturnal delirium, confusion, restlessness, disorientation, drowsiness, memory loss, abnormal behavior (aggression, irritability, and hyperactivity), seizures, and coma.

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.

Acute hyperammonemia · Very frequent (99-80%)

An increased concentration of ammonia in the blood with sudden onset.

Decreased body mass index · Very frequent (99-80%)

Abnormally decreased weight-to-height squared ratio, calculated by dividing the individual's weight in kilograms by the square of the individual's height in meters and used as an indicator of underweight compared to averages.

Elevated plasma citrulline · Very frequent (99-80%)

The concentration of citrulline in the blood circulation is above the upper limit of normal.

Hepatic steatosis · Very frequent (99-80%)

Steatosis is a term used to denote lipid accumulation within hepatocytes.

Abnormal eating behavior · Frequent (79-30%)

Abnormal eating habits involve excessive or insufficient consumption of food, or any other abnormal pattern of food consumption.

Aggressive behavior · Frequent (79-30%)

Behavior or an act aimed at harming a person, animal, or physical property (e.g., acts of physical violence; shouting, swearing, and using harsh language; slashing someone's tires).

Asterixis · Frequent (79-30%)

A clinical sign indicating a lapse of posture and is usually manifest by a bilateral flapping tremor at the wrist, metacarpophalangeal, and hip joints.

Confusion · Frequent (79-30%)

Lack of clarity and coherence of thought, perception, understanding, or action.

Delirium · Frequent (79-30%)

A state of sudden and severe confusion.

Delusion · Frequent (79-30%)

A delusion is a fixed false belief held despite evidence to the contrary. The term delusion broadly encompasses all false judgments that possess the following external characteristics to a significant, albeit unspecified, extent: (1) they are held with an exceptional level of conviction, accompanied by an unparalleled subjective certainty; (2) there is an inability to consider alternative experiences or compelling counter-arguments; (3) the content of the belief is impossible.

Drowsiness · Frequent (79-30%)

Abnormal feeling of sleepiness or difficulty staying awake.

Elevated circulating hepatic transaminase concentration · Frequent (79-30%)

Elevations of the levels of SGOT and SGPT in the serum. SGOT (serum glutamic oxaloacetic transaminase) and SGPT (serum glutamic pyruvic transaminase) are transaminases primarily found in the liver and heart and are released into the bloodstream as the result of liver or heart damage. SGOT and SGPT are used clinically mainly as markers of liver damage.

Fluctuations in consciousness · Frequent (79-30%)

Changes in one's level of awareness and responsiveness to their environment.

Hallucinations · Frequent (79-30%)

Perceptions in a conscious and awake state that, in the absence of external stimuli, have qualities of real perception. These perceptions are vivid, substantial, and located in external objective space.

Other findings in the same source

From: Orphanet

Additional reported features include Hepatomegaly (Frequent (79-30%)); Hyperlipidemia (Frequent (79-30%)); Hypertriglyceridemia (Frequent (79-30%)); Hypoalbuminemia (Frequent (79-30%)); Hypoproteinemia (Frequent (79-30%)); Irritability (Frequent (79-30%)); Lethargy (Frequent (79-30%)); Memory impairment (Frequent (79-30%)); Night sweats (Frequent (79-30%)); Restlessness (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Adult

Inheritance in the source

From: Orphanet

Autosomal recessive

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 Citrullinemia type II is Metabolic Medicine, with a metabolic specialist / clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with metabolic specialist / 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.

• Is a biochemical or molecular result needed to clarify the diagnosis?
• Does this condition require an individual plan for illness or reduced food intake?
• Should nutrition advice come from a specialist metabolic dietitian?

Treatment discussions and follow-up

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