← All diseases

Inborn errors of metabolism

Maple syrup urine disease (MSUD)

An inherited disease in which the body cannot process certain amino acids. It is named after the sweet smell of the urine. The most common type begins shortly after birth; if it is not recognized, it is life-threatening.

Not part of the panel of Türkiye's National Newborn Screening Programme (heel-prick test). Source

Orphanet has a guideline for emergency doctors for this disease (language: English, French). See on Orphanet

Prepare an emergency card

This page is translated from the Turkish original.

This disease is followed through the “Inborn errors of metabolism” group.

Understanding the disease

This section has not yet been reviewed by a physician. It summarises patient information from sources such as MedlinePlus, Orphanet and the NHS in plain language. The disease can differ from person to person; talk to your doctor about diagnosis and treatment.

What happens in this disease?

In this disease, the body cannot break down three amino acids (the building blocks of proteins). These substances rise to harmful levels in the blood. The brain in particular can be damaged. The disease gets its name from the sweet smell of the urine.

Which symptoms can occur?

The classic type, which is the most common, begins in the first days after birth. Milder types can appear in infancy or childhood.

  • Difficulty feeding and vomiting (common in the classic type)
  • Drowsiness and excessive sleepiness (common in the classic type)
  • Sweet smell of the urine (common)
  • Unusual movements (sometimes)
  • Developmental delay (sometimes)
  • In some types, attacks that come only at certain times (sometimes)
  • If not treated, seizures and coma (life-threatening)

How is it diagnosed?

The disease can be detected early through newborn screening. This screening shows that certain amino acids in the blood are high. The diagnosis is confirmed with further tests.

Treatment and care

The main approach is a special diet that limits these amino acids. There is an emergency treatment plan to follow during attacks. In one type, vitamin B1 treatment is helpful. Early diagnosis and fast treatment markedly improve the outcome. The doctor who follows the disease decides which treatment is suitable.

For the family: inheritance and genetic counselling

To have the disease, a person must receive one changed gene from the mother and one from the father. Carrier mothers and fathers often have no symptoms. In each pregnancy, the chance that the child is affected is 1 in 4. Genetic counselling is recommended.

Source: MedlinePlus Genetics — Maple syrup urine disease · Orphanet — Maple syrup urine disease (ORPHA:511)

Key facts

How common is it?
Prevalence: 1-9 per 1 000 000 (Europe) · Birth prevalence: 1-9 per 1 000 000 (Worldwide)
How is it inherited?
Autosomal recessive
When does it usually start?
Newborn period, Infancy, Childhood
Gene(s) involved
BCKDHA, BCKDHB, DBT, PPM1K

These facts are taken from Orphanet and MedlinePlus records (last checked: October 7, 2026). Frequency values are approximate ranges.

You are not alone: patient associations in Türkiye

Non-profit patient and family organizations in Türkiye working on this disease or disease group. Links are for information; Doktorclub is not affiliated with these organizations and does not endorse them.

For all rare diseases: Nadir Hastalıklar Federasyonu

Links checked on October 8, 2026.

Guides related to this disease

  • Special diets and medical nutrition · Metabolic diet, blood monitoring, medical formula and SGK report, sick-day plan, tube feeding and swallowing problems, school meals, supplement warning
  • Rare disease at school · Telling the school, medicines and emergency plan, inclusion and BEP, support education room, absences, LGS/YKS arrangements, peer bullying.

Support and help

Doktorclub does not diagnose, recommend treatments or refer you to hospitals or doctors. These pages are meant to help you talk with your doctor.

News about MSUD

Clinical trials (ClinicalTrials.gov)

A clinical trial is a regulated study that tests whether a new treatment is safe and whether it works, in patients who volunteer. Most trials look for a certain age, genetic change and health condition. Taking part is voluntary.

This list is not a treatment recommendation. Treatments tested in phase 1–3 trials are investigational (experimental): their efficacy and safety have not yet been proven and they are not approved treatments. Taking part depends on each trial’s criteria and a physician’s assessment; the first step is to talk to the doctor who manages your care.

Questions you can ask your doctor

  • Could this trial be suitable for us?
  • If we take part, how would current treatment and check-ups be affected?
  • Where does the trial take place, and how are travel and accommodation handled?
  • What happens if we want to leave the trial?

ClinicalTrials.gov lists 1 active interventional study for this disease. None is recruiting right now; none has a site in Türkiye. Last checked: October 7, 2026.

Selected records (studies with a site in Türkiye first):

See all studies on ClinicalTrials.gov · Joining clinical trials

Inborn errors of metabolism: other news

Medical codes (for talking with your doctor and finding sources)

These codes identify the disease in international classifications and databases. They can help when you talk with your doctor or look for reliable sources.

Orphanet code: ORPHA:511 · ICD-11 5C50.D0

Codes checked against WHO ICD-11 and Orphanet on October 6, 2026.

This page provides general information and does not replace diagnosis or treatment. Talk to your doctor about symptoms, diagnosis and treatment.

The information on these pages is for general information only and does not replace medical advice. Talk to your doctor about diagnosis and treatment decisions. In an emergency in Türkiye, call 112.

Every update is based on an open source and labeled with its level of evidence. No advertising and no drug brand names. Our scientific principles

This page was translated from Turkish by the Doktorclub editorial team.