Written by Dr. Priyanshu Mathur, State Nodal Officer for Rare Diseases, Rajasthan
Hunter syndrome, or mucopolysaccharidosis type II (MPS II), is a tragic example of how genetic conditions can dramatically alter the lives of affected individuals but remain largely invisible to society. MPS II is not just a medical diagnosis but a call to action regarding increased awareness, early intervention, and most importantly, equitable health care.
MPS II arises from a deficiency of the enzyme iduronate-2-sulfatase (IDS), which is essential for breaking down glycosaminoglycans (GAGs) in the body. In their absence, GAGs accumulate in cells, causing progressive destruction in multiple organ systems. It is linked to the X chromosome and occurs mainly in males, but in rare cases it can be observed in females due to aberrant inactivation of the X chromosome.
Symptoms usually appear between the ages of 18 and 36 months, although there is a wide range of presentations, often classified into severe and debilitating forms. In the severe type, common in two-thirds of patients, children develop progressive mental impairment, decreased growth, and behavioral disturbances, including hyperactivity or aggression. Physical signs can include coarse facial features, i.e. a broad nose, enlarged tongue and forehead, short stature, joint stiffness, and skeletal deformities such as a broad chest, or certain deformities of the spine. There are frequent respiratory complications, such as upper airway obstruction, sleep apnea, and recurrent infections due to bronchoconstriction and poor mucus clearance.
Spread of MPS II in India
In India, the prevalence is estimated at 3.5-4.5 Per 100,000 live births, based on analyzes of global IDS genetic variants, India accounts for 5.8% of cases reported worldwide. This scarcity makes it invisible in population health discourse, but increases the urgency to raise awareness; Scarcity should not be taken as negligence. The progressive complexity means that life expectancy in extreme cases without treatment may be poor 10-15 yearswhich is mainly associated with respiratory or cardiac failure. In mild cases, they can live to their old age The sixtiesBut due to chronic pain and disability, the quality of life decreases.
Based on prevalence data, India’s large population translates these numbers into a significant patient burden. As of 2023-2024, lysosomal storage disorder support groups have reported about 180 officially registered children with Hunter syndrome in India. However, this is likely to be under-reported as most cases may remain undiagnosed, as access to genetic testing and awareness among primary care providers is limited in the country.
Availability of ERT in India
There is no cure for MPS II, and enzyme replacement therapy (ERT) is one of the mainstays of treatment, which aims to provide the missing IDS enzyme and slow enzyme accumulation. Masks. Given as a weekly intravenous infusion, ERT has been shown to improve physical symptoms, such as joint range, respiratory function, and even organ size, but the drug fails to penetrate the blood-brain barrier, limiting its effectiveness in treating cognitive impairment.
ERT exists in India, but is not evenly distributed because it is expensive and logistically difficult to access. Such approved treatments require multidisciplinary treatment, including pediatricians, pulmonologists, neurologists, and therapists. Organizations such as the MPS Society and lysosomal storage disorder support groups advocate for subsidized access, but many families face out-of-pocket expenses that escalate with the child’s weight. New interventions, including hematopoietic stem cell transplantation (HSCT) in early severe cases, hold promise for halting progression, including neurological outcomes, but carry risks and are limited to specialized institutions.
Prenatal genetic counseling and carrier screening efforts are crucial in India, given the presence of the X-linked type of inheritance, and enabling informed reproductive decision-making by family members is essential.
Raising awareness: a team effort
MPS II makes us reconsider the “right to life” not simply as survival, but as early diagnosis, accessible care and comprehensive assistance. Families endure the invisible labor associated with coordinating treatments, emotional exhaustion, and advocating for resources, which often occurs without adequate mental health integration. Knowledge is the antidote to stigma; Genetic counseling replaces guilt with awareness and understanding.
Policymakers, clinicians and communities need to focus on rare diseases. Offer newborn screening, invest in research, and create support groups. Early intervention can change someone’s future; However, delay turns the potential into a huge loss.
About the author
Dr. Priyanshu Mathur is the Rajasthan State Nodal Officer for Rare Diseases. Dr. Mathur holds MSc in Pediatrics, Fellowship in Metabolic Genetic Disorders and Newborn Screening (USA), MSc in Neurometabolism and Cell Biology for Physicians (Spain) and PhD in Genetics (Honoris).
