MSUD Introduction

The Expanded Newborn Screening project has now ended.  As a result of this project screening for this disorder will continue at the pilot sites, and will start at all other sites in England from early 2015.  The information provided in these pages is no longer being actively maintained, and all the information leaflets and technical resources have been superseded by those produced by the NHS Newborn Blood Spot Screening Programme.

Please use the following pages (film and leaflets, resources and fact file) to find out more information about MSUD.

What does MSUD stand for?

MSUD stands for Maple Syrup Urine Disease. 

What is MSUD?

MSUD is a rare disorder in which a baby or child has a problem breaking down particular amino acids known as leucine, isoleucine and valine contained within protein.   For people with MSUD, eating too much protein can cause a harmful build up of these amino acids in the blood.

What is an amino acid?

Amino acids are the building blocks of protein and make up a large proportion of the human body.  Normally, people get protein in foods such as meats and the body uses them to help keep the tissues of the body healthy.  Amino acids which are not needed are broken down and removed from the body.  People with MSUD are unable to break down some of the amino acids (called leucine, isoleucine and valine – these are also known as the branched chain amino acids). When the levels of these amino acids get very high, they are harmful.

What are the effects of having MSUD?

Many babies with MSUD become unwell when they are a few days old, with:

  • poor feeding
  • vomiting
  • excessive sleepiness

Without treatment, this leads to a coma and permanent brain damage. In older children a minor illness, such as a chest infection or a tummy upset, can lead to serious problems. The early signs in older children include confusion and poor balance as well as loss of appetite, vomiting and excessive sleepiness. As in babies, this can lead to a coma unless treated correctly.

How is MSUD treated?

MSUD is treated with a special low protein diet which is used to prevent the build up of harmful amino acids in the blood.   Special supplements are needed as part of this diet, along with regular blood tests.

During illnesses, protein feeds should be stopped. The child is given special drinks, known as the Emergency Regimen; if the child vomits these, he or she needs to go to hospital.