Multiple Sulfatase Deficiency (MSD) is a condition that affects the entire body. Various mutations of the SUMF1 gene are known to be the cause of MSD. There are very few known cases of MSD, so the description below is what we have gathered from our personal research, doctor’s input and families across the world.
MSD is a lysosomal storage disease where the body is not breaking down and filtering out the natural cellular waste that occurs in everyday cell functions. This cell waste builds up over time and is deposited throughout the body in multiple systems. Children are typically without any symptoms at birth but over time, the cellular waste deposited throughout the body leads to problems.The brain begins to gather white matter, causing developmental delay, and loss of motor and communication skills. Some children with MSD may talk initially, but then as the brain is affected they will lose their verbal skills. Some children with MSD will never develop speech. The cellular waste can build up in the eyes, which may cause blindness. The deposit of cellular waste in the throat can cause difficulty swallowing and breathing. Combined with the problems caused in the brain by MSD, many children will require a feeding tube be placed directly into their stomach or intestines to ensure that they are able to receive nutrition.
In addition to problems in the throat from a build up of cellular waste, there are other symptoms which manifest in the ears, nose and throat. Often, these symptoms are some the first to present and it is fairly typical for children with MSD to have ear tubes from frequent infection. Frequent congestion and other upper respiratory infections are common. As the disease progresses and swallowing slows, aspiration of liquids can cause pneumonia.
The bones are affected by the buildup of cellular waste causing deformation of the spine as the body grows. Curvature of the spine (scoliosis) and joint stiffness often also occur in children with MSD.
Balance issues can appear early in the disease process. This may be caused by a combination of the build up of cellular waste in the brain, nervous system, and bones. Children usually stop walking and crawling as the disease progresses.
Heart conditions and circulatory problems can arise because of the build up of cellular waste in the heart and vascular system.
Children with MSD typically suffer severe dry skin on the back, stomach and scalp. Clinically, facial features of MSD children are described as “course”. The eyebrows and eyelashes are often usually long.
MSD is fatal. With no current treatment options available, many children do not live past 10 years old.
The Science of MSD
Multiple Sulfatase Deficiency (MSD) is a rare, inherited metabolic disorder caused by mutations in the SUMF1 gene, which encodes the Formylglycine-Generating Enzyme (FGE).
This enzyme is required for the posttranslational modification of every cellular sulfatase. Defective FGE function results in absent sulfatase activities, many of them within the lysosomes, and build-up of sphingolipids mucopolysaccharides.
MSD is a fatal condition combining symptoms of single sulfatase deficiencies. Symptoms include developmental delay, neurodegeneration resulting in a loss of motor and communication skills, spasticity and epilepsy. Additional symptoms like hepatosplenomegalie, dysostosis multiplex, hydrocephalus, inguinal hernias, and ichthyosis occur in patients with MSD. Onset and progress of symptoms in MSD allow for the differentiation of a neonatal very severe form of the disease, a late infantile severe and mild form and a juvenile form of MSD.