A toddler with a deadly genetic disorder survived, thanks to gene therapy. Unfortunately, the treatment was too late to save her sister.
Gene Therapy to Treat Metachromatic Leukodystrophy
A toddler became the first NHS (National Health Service) patient to receive the $3.6 million gene therapy for metachromatic leukodystrophy (MLD), a rare condition that ravages the organs and nervous system.
The 19-month-old toddler, Terri, was diagnosed with the disease last April. Her older 3-year-old sister Nala was also diagnosed with MLD at the same time, Mirror reported.
Patients with MLD have a life expectancy between five and eight years, so both girls would have died during their childhood if not for the treatment.
Fortunately, Teddi was cured after undergoing gene therapy, where the stem cells are removed, and the faulty genes are replaced before the treated cells are re-injected.
Unfortunately, Nala was not eligible because NHS rules the therapy must only be administered before irreversible damage has progressed, causing problems in the child's sight, speech, hearing and movement.
Ally, 32, the mother of two kids with MLD said their world turned upside down when they learned their daughters were diagnosed with MLD. The heartbreaking part was Nala was ineligible for the treatment because they would see her lose all functions and die at an extremely young age.
Despite what happened, they were still thankful that Teddi qualified; otherwise they would lose both daughters. They were hopeful that Teddi would live a long and normal life.
Ally said Teddi is doing good and is walking and running. She added that there were no signs of MLD so far. However, she hoped that one day a treatment for all stages of MLD would be available. She also suggested that it should be added to the newborn screening test to save more families from heartache.
NHS chief Amanda Pritchard said Teddi's case gave parents huge hope because it showed that babies born with the devastating inherited disorder can now do things that other children do, like going to school and playing with their friends.
What is Metachromatic Leukodystrophy?
According to Mayo Clinic, metachromatic leukodystrophy is a rare genetic disorder that causes the accumulation of fatty substances (lipids) in cells, especially in the brain, spinal cord, and peripheral nerves. This buildup is caused by an enzyme deficiency that hinders the breakdown of lipids called sulfatides. Myelin, the substance that covers and protects nerve cells, is harmed, resulting in a progressive decline in brain and nervous system function.
Mutations in the ARSA or PSAP genes cause a deficiency of the enzyme arylsulfatase A and a diminished ability to break down sulfatides in individuals with MLD. Sulfatides are essential myelin sheath components. However, an excess of sulfatides can be toxic to the nervous system, destroying myelin-producing cells and resulting in nervous system dysfunction, the National Institute of Neurological Disorders and Stroke added.
The prognosis for MLD is dismal. The majority of infants die by age 5 at the earliest. The progression of symptoms in the juvenile form results in death 10 to 20 years after onset. People with the adult form of the disease typically pass away between six and 14 years after the onset of symptoms.
Given that MLD is an inherited disorder, it is not uncommon for two siblings to have it. When the older sibling displays symptoms, the younger sibling is often tested.
MLD can be carried by asymptomatic individuals. In the absence of a family history of the disorder, it is typically diagnosed using a combination of brain MRI, blood, and urine tests, followed by genetic testing to identify the specific mutation.
A patient's child has a 25% chance of contracting the disease, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier.
Prof. Simon Jones, director of the Manchester Centre for Genomic Medicine and the Royal Manchester Children's Hospital, stated that there was no approved treatment before the NHS made this service available. There are a number of subtypes of the disease, but in the later stages, all of them cause children to lose the ability to move and speak.
Jones said he has treated numerous patients with MLD in its advanced stages and can attest to its devastation. He was ecstatic to be one of five European centers providing gene therapy for MLD.
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