Sialuria

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Sialuria is a rare disorder that affects development. Infants with sialuria are often born with a yellow tint to the skin and the whites of the eyes (neonatal jaundice), an enlarged liver and spleen (hepatosplenomegaly), and unusually small red blood cells (microcytic anemia). They may develop a somewhat flat face and distinctive-looking facial features that are described as "coarse." Temporarily delayed development and weak muscle tone (hypotonia) have also been reported.

Young children with sialuria tend to have frequent upper respiratory infections and episodes of dehydration and stomach upset (gastroenteritis). Older children may have seizures and learning difficulties. In some affected children, intellectual development is nearly normal.

The features of sialuria vary widely among affected people. Many of the problems associated with this disorder appear to improve with age, although little is known about the long-term effects of the disease. It is likely that some adults with sialuria never come to medical attention because they have very mild signs and symptoms or no health problems related to the condition.

ORPHANET DEFINITION A rare disorder of sialic acid metabolism characterized by excretion of large quantities of free sialic acid (predominantly N-acetylneuraminic acid without any morphologic evidence of storage within any subcellular organelle), mildly coarse facial features and hepatosplenomegaly. Growth and development are rather normal, however some affected individuals were reported to have moderate developmental delay, slight motor delay and mild intellectual impairment. Additional clinical features may involve macrocephaly, mild small airway obstruction, frequent upper respiratory tract infections, transient failure to thrive, seizures and sleep apnea. Signs and symptoms can be transient, especially in infancy.

Inheritance

From: MedlinePlus Genetics, National Library of Medicine

Autosomal dominant+New variant

Frequency in the source

From: MedlinePlus Genetics, National Library of Medicine

Reported case(s): 5.0; Worldwide. This is a published case count, not prevalence. Point prevalence: <1 / 1 000 000; Worldwide; Class only.

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.

2-3 toe syndactyly · Very frequent (99-80%)

Syndactyly with fusion of toes two and three.

Abnormal facial shape · Very frequent (99-80%)

An abnormal morphology (form) of the face or its components.

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

An anomaly of the mitochondrion, the membranous cytoplasmic organelle the interior of which is subdivided by cristae. The mitochondrion is a self replicating organelle that is the site of tissue respiration.

Attention deficit hyperactivity disorder · Very frequent (99-80%)

Attention deficit hyperactivity disorder (ADHD) manifests at age 2-3 years or by first grade at the latest. The main symptoms are distractibility, impulsivity, hyperactivity, and often trouble organizing tasks and projects, difficulty going to sleep, and social problems from being aggressive, loud, or impatient.

Cholelithiasis · Very frequent (99-80%)

Hard, pebble-like deposits that form within the gallbladder.

Coarse facial features · Very frequent (99-80%)

Absence of fine and sharp appearance of brows, nose, lips, mouth, and chin, usually because of rounded and heavy features or thickened skin with or without thickening of subcutaneous and bony tissues.

Elevated circulating hepatic transaminase concentration · Very frequent (99-80%)

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.

Epicanthus · Very frequent (99-80%)

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.

Episodic abdominal pain · Very frequent (99-80%)

An intermittent form of abdominal pain.

Expressive language delay · Very frequent (99-80%)

A delay in the acquisition of the ability to use language to communicate needs, wishes, or thoughts.

Generalized hypotonia · Very frequent (99-80%)

Generalized muscular hypotonia (abnormally low muscle tone).

Hepatomegaly · Very frequent (99-80%)

Abnormally increased size of the liver.

Hepatosplenomegaly · Very frequent (99-80%)

Simultaneous enlargement of the liver and spleen.

High, narrow palate · Very frequent (99-80%)

The presence of a high and narrow palate.

Other findings in the same source

From: Orphanet

Additional reported features include Hoarse voice (Very frequent (99-80%)); Hyperkinetic movements (Very frequent (99-80%)); Hypertelorism (Very frequent (99-80%)); Intellectual disability, mild (Very frequent (99-80%)); Joint hypermobility (Very frequent (99-80%)); Long hallux (Very frequent (99-80%)); Low-set ears (Very frequent (99-80%)); Memory impairment (Very frequent (99-80%)); Periorbital fullness (Very frequent (99-80%)); Prolonged partial thromboplastin time (Very frequent (99-80%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: MedlinePlus Genetics, National Library of Medicine

Infancy

Inheritance in the source

From: MedlinePlus Genetics, National Library of Medicine

Autosomal dominant+New variant

Frequency and the population described

From: MedlinePlus Genetics, National Library of Medicine

Reported case(s): 5.0; Worldwide. This is a published case count, not prevalence. Point prevalence: <1 / 1 000 000; Worldwide; Class only.

Which doctor should you see?

The suggested department for discussing Sialuria 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 Sialuria. 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.