Improved Cognition in Hurler Syndrome Using Cord Blood Transplant

stem cell studies

A recent study demonstrates that the babies affected by Hurler syndrome can be protected from permanent brain damage, if diagnosed and treated earlier within 9 months of age through umbilical cord stem cell transplants.

Living with Hurler Syndrome

Hurler syndrome is an inherited metabolic disorder caused by a defective gene that cannot synthesize lysosomal α– L- iduronidase, an important metabolic enzyme required to break down the large molecule of sugar chain, glycosaminoglycans (GAG) 1. This molecule is critical for the development of the body as it helps in building the bones and tissues. In patients with Hurler syndrome, the body cannot break down the GAG molecules, leaving them to build up and damage all the vital organs including brain2.

Hurler syndrome is the most severe form of mucopolysaccharidosis conditions which cause fatal multisystem deterioration. Although the children appear normal at birth, they progressively get worse as the symptoms manifest over the first few years of life due to the building up of polysaccharides that damage the organs and tissues. This syndrome affects the development of skeletal system, respiratory system, circulatory system, organs such as heart, brain etc., and causes limited cognitive abilities, unique facial structures, arrested skeletal growth, abnormal bones in the spine, heart valve problems, claw hand, joint diseases, intellectual disability, deafness, cloudy vision etc1. As the child grows, the condition becomes severe and fatal. The children affected with Hurler syndrome usually live between 5 and 10 years of age2.

Treating HS with Cord Blood Transplant

The umbilical cord blood transplant is used as one of the treatment options for Hurler syndrome from the early 1980s. It is considered as a suitable treatment for this condition because it serves as a permanent replacement for the production of the cellular enzyme in the patients 3. However, bone marrow transplant procedure is also considered as a treatment option.

The treatment involves chemotherapy which destroys the diseased cells and prepares the body for transplant. The umbilical cord cells or the bone marrow from unrelated donors are infused into the affected person’s blood stream which will reach the bone marrow and produce healthy blood cells (RBCs, WBCs and platelets) that can produce the required enzyme2. Although the damages caused were irreversible through this treatment, it will arrest the disease progression and prevent any further defect. When compared to bone marrow, umbilical cord stem cells from donors showed better results over the years and proved to improve the lives of affected children4.

Role of Early Detection and Treatment

Based on a new study by University of Pittsburgh School of Medicine, if the babies with hurler syndrome are treated with hematopoitic stem cells before the age of 9 months, they can have normal cognitive development. This early treatment also showed better language skills and adaptive behaviours 5. Thus early diagnosis is the key to improve the cognition abilities of children affected with Hurler syndrome.

Maria Luisa Escolar, the associate professor of pediatrics at University of Pittsburgh School of Medicine says, “This study highlights the importance of early detection of brain diseases in babies and infants when brain growth is the most accelerated in life, placing them at increased vulnerability for permanent damage.”

What can be done?

  • If there is a family history of hurler syndrome, it is essential to opt for prenatal diagnosis or new born screening to detect the condition. There are prenatal tests and newborn screening available to detect for hurler syndrome in babies
  • After detection, try to initiate the transplant procedure as early as possible based on the availability of donor stem cells and it is essential to continue the treatment.
  • It is also important to create awareness about the condition, benefits of early detection and the use of public cord blood donation in the society.




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