Autosomal dominant hyperinsulinism due to SUR1 deficiency

What it is

From: Orphanet

A form of congenital diazoxide-sensitive diffuse hyperinsulinism due to ABCC8 variants and characterized by hypoglycemic episodes that are usually mild, escaping detection during infancy, and usually have a good clinical response to diazoxide. The autosomal dominant hyperinsulinism usually has a milder phenotype when compared to that resulting from recessive potassium (K-ATP) channel mutations.

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.

Excessive insulin response to glucagon test · Very frequent (99-80%)

An abnormally high increase in insulin levels following a glucagon stimulation test.

Hyperinsulinemia · Very frequent (99-80%)

An increased concentration of insulin in the blood.

Hyperinsulinemic hypoglycemia · Very frequent (99-80%)

An increased concentration of insulin combined with a decreased concentration of glucose in the blood.

Hypoketotic hypoglycemia · Very frequent (99-80%)

A decreased concentration of glucose in the blood associated with a reduced concentration of ketone bodies.

Increased C-peptide level · Very frequent (99-80%)

The concentration of C-peptide in the blood circulation is above the upper limit of normal.

Decreased circulating free fatty acid level · Very frequent (99-80%)

Fasting hypoglycemia · Very frequent (99-80%)

Agitation · Frequent (79-30%)

A state of excessive motor activity that is associated with mental distress or a feeling of substantial unease or inner tension. Distinguished from restlessness by the increased level of emotional distress and negative intensity of the experience. Agitation has a significant level of physical activity that is typically threatening to the self or others.

Diffuse pancreatic islet hyperplasia · Frequent (79-30%)

Hyperplasia of the islets of Langerhans with a generalized distribution.

Drowsiness · Frequent (79-30%)

Abnormal feeling of sleepiness or difficulty staying awake.

Episodic hyperhidrosis · Frequent (79-30%)

Intermittent episodes of abnormally increased perspiration.

Focal pancreatic islet hyperplasia · Frequent (79-30%)

Hyperplasia of the islets of Langerhans that affects only certain regions of the pancreas and not others.

Large for gestational age · Frequent (79-30%)

The term large for gestational age applies to babies whose birth weight lies above the 90th percentile for that gestational age.

Neurodevelopmental abnormality · Frequent (79-30%)

A deviation from normal of the neurological development of a child, which may include any or all of the aspects of the development of personal, social, gross or fine motor, and cognitive abilities.

Other findings in the same source

From: Orphanet

Additional reported features include Pallor (Frequent (79-30%)); Palpitations (Frequent (79-30%)); Tachycardia (Frequent (79-30%)); Hypoglycemic seizures (Frequent (79-30%)); Feeding difficulties (Occasional (29-5%)); Hepatomegaly (Occasional (29-5%)); Hypertrophic cardiomyopathy (Occasional (29-5%)); Hypoglycemic coma (Occasional (29-5%)); Lethargy (Occasional (29-5%)); Loss of consciousness (Occasional (29-5%)). 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

Autosomal dominant

Understanding the inheritance label

From: MedlinePlus Genetics

An autosomal dominant pattern means that one altered copy of a relevant gene can be sufficient for the condition. Some affected people inherit the change; others have a new change without an affected parent. The precise finding, family history and condition determine what this means for relatives.

Which doctor should you see?

The suggested department for discussing Autosomal dominant hyperinsulinism due to SUR1 deficiency 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 Autosomal dominant hyperinsulinism due to SUR1 deficiency. 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.