Bone marrow transplant helps hand-eye coordination in Sanfilippo child
But more research needed to validate, expand on results of small study
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A bone marrow transplant may help improve motor function in children with Sanfilippo syndrome, according to a new study from China in which one youngster with the rare genetic disorder had better hand-eye coordination after undergoing the procedure.
While the study overall involved dozens of children with similar genetic disorders, this child was the only one specifically diagnosed with Sanfilippo. As such, the scientists cautioned that there’s a need for additional research to validate and expand on the results.
“[A transplant] stabilizes/improves neurodevelopment in [children with these conditions],” the team wrote, but noted that the outcomes are “modulated by [disease] subtype and transplant age.”
The study, “Allogeneic hematopoietic stem cell transplantation modulates neurodevelopmental trajectories in mucopolysaccharidosis: a longitudinal study of subtype-specific outcomes and age-dependent efficacy,” was published in the Orphanet Journal of Rare Diseases.
Mucopolysaccharidosis, or MPS, refers to a group of genetic disorders in which the body is unable to break down certain sugar molecules. This results in the accumulation of sugars to toxic levels within cells, causing damage.
Sanfilippo syndrome, also called MPS type III, is specifically marked by a buildup of a sugar molecule called heparan sulfate, resulting in developmental abnormalities and other disease symptoms.
The bone marrow is home to hematopoietic stem cells (HSCs), which are responsible for making new blood cells and immune cells. An allogeneic HSC transplant, also commonly referred to as a bone marrow transplant, is a procedure in which a person’s HSCs are eliminated and replaced with those from a donor.
Little data on impact of bone marrow transplant in MPS
Theoretically, a bone marrow transplant might benefit people with Sanfilippo and other forms of MPS by enabling the body to produce some cells that can break down heparan sulfate. This might include immune cells that can help clear this toxic sugar molecule from the brain.
However, the transplant itself is a very invasive procedure with a high risk of serious or life-threatening side effects. Moreover, there’s not much data on how a bone marrow transplant affects long-term outcomes in people with MPS.
In this study, scientists in China reported on outcomes following bone marrow transplant in 57 children with various types of MPS. Most of the children in the study specifically had MPS type I (Hurler syndrome) or MPS type II (Hunter syndrome); one child was diagnosed with Sanfilippo.
All of the children were assessed using a Chinese version of the Griffiths Development Scales, which measures childhood development across six domains: motor function, hand-eye coordination, language, practical reasoning, visual performance, and social skills.
Results from all patients showed a tendency toward reported improvements in motor function, hand-eye coordination, and language following bone marrow transplant. Some modest gains were also reported in the social skills domain.
The researchers noted, however, that outcomes following the transplant differed significantly between different types of MPS.
“These findings underscore the necessity of subtype-tailored therapeutic approaches,” the team wrote.
Child with Sanfilippo experienced short-term motor function gains
In the one patient with Sanfilippo, there was a substantial improvement in hand-eye coordination following bone marrow transplant, as well as a short-term improvement in motor function.
The scientists stressed that, though, that with only one Sanfilippo patient in the study, it’s impossible to draw broad conclusions about how a bone marrow transplant is likely to affect people with this particular type of MPS. The team highlighted the need for additional studies involving larger numbers of patients.
“Multicenter randomized trials comparing conventional rehabilitation with intensive neurodevelopmental interventions are warranted to establish evidence-based guidelines for MPS management,” the scientists wrote.
