HYDERABAD: The scope for treatment of rare disorders has been expanding with introduction of new diagnostic tools and techniques. However, awareness about such diseases among the public and medical fraternity needs improvement. Although rare, there are around 8,000 rare diseases that affect over seven crore people in India.
“Detecting conditions before a baby shows any symptoms and then, initiating early treatment can afford the child a normal life, akin to their peers,” said Dr Radha Rama Devi, senior paediatrician and clinical geneticist at Rainbow Children’s Hospital. A pre-symptomatic diagnosis is possible through screening programmes such as newborn screening.
In India, a comprehensive screening of every newborn is conducted, checking for known, common and treatable disorders. “A small blood sample taken shortly after birth helps detect conditions like hypothyroidism, a treatable disorder that can lead to intellectual disability if not addressed. Despite being cost-effective, there’s a need for increased awareness among the medical professionals to ensure widespread implementation of newborn screening for early detection and intervention,” the paediatrician added.
“Over 80% of rare diseases in India are genetic, such as phenylketonuria (PKU), where the amino acid phenylalanine accumulates in the body,” said Radha. She also highlighted the challenges in diagnosing rare diseases, as it often takes two to seven years. “While progress is being made, diagnostic facilities are predominantly emerging in developed metropolitan cities, leaving rural and district areas with undiagnosed cases. Efforts are needed to extend diagnostic capabilities to grassroots level for comprehensive rare disease management,” she said.
The role of genetics
Given the multitude of genetic disorders with overlapping features, a conclusive diagnosis often relies on genetic testing. “Intellectual disability, for instance, can be associated with over 500 disorders, making clinical assessments or imaging like MRI insufficient. A genetic test becomes crucial for confirmation,” said Dr Ashwin Dalal, a scientist in the Centre for DNA Fingerprinting and Diagnostics (CDFD), the CoE in Hyderabad.
The diagnostic journey often spans many years, beginning with visits to paediatricians or medical specialists. Referral to a geneticist is pivotal for initiating genetic tests, making it crucial for basic clinicians to suspect a genetic link early on. Specific genetic tests are tailored to each disease and early detection allows preventive measures for subsequent generations.
“In the last decade, next-generation sequencing has revolutionised genetic testing, enabling comprehensive genome analysis. This technological advancement has significantly enhanced the diagnosis of various genetic conditions. Elevated awareness significantly shortens the diagnosis period, enabling prompt treatment for patients and facilitating the early detection and prevention of diseases. Recent breakthroughs, particularly in gene therapy, have expanded treatment options, albeit at considerable costs,” Ashwin said.
He added that lack of awareness persists at multiple levels—from lay people unaware of alternative possibilities to paediatricians and obstetricians who may not recognise the need for genetic referrals. This contributes to an average delay of six to seven years in diagnosis. “Elevated awareness significantly shortens the diagnosis period, enabling prompt treatment for patients and facilitating the early detection and prevention of diseases,” he said.
The World Health Organisation defines rare diseases having prevalence of one or less per 1,000 populations. As only a small number of individuals are impacted by these diseases, pharmaceutical, insurance companies and government entities often neglect it. As the market for such drugs is small, pharmaceutical companies don’t take interest in it. It is why rare diseases are often called ‘orphan diseases’ and drugs for them termed ‘orphan drugs.’ In the National Policy for Rare Diseases, 2021, the government has categorised rare diseases into three groups. Group-1 includes disorders amenable to one-time curative treatment through transplantation; group-2 includes diseases requiring long term or lifelong treatment having relatively low cost of treatment; whereas, group 3 includes diseases for which definitive treatment is available but challenges are to make optimal patient selection for benefit, very high cost and lifelong therapy.
In India, Gaucher disease is relatively common, and the available treatment involves enzyme replacement. Administering this replacement to a child within the first year can potentially reverse the disease, restoring a normal situation. However, the significant obstacle lies in the high cost, as for example, treating a 10kg child costs `50 lakh per year lifelong. This expense renders such high-end treatments unaffordable for many, even challenging for government support unless more accessible solutions emerge to assist those in need, added Dr. Devi.
The national policy also provides one-time financial support up to `50 lakh for treatment in any of the eight centres of excellence (COEs) in India - Delhi, Lucknow, Chandigarh, Hyderabad, Mumbai, Kolkata and Bengaluru. However, as experts suggest, a lot of clarity and improvements are needed in the policy. A lot of governments and officials are not even aware of it.
Pompe disease
Also recognised as glycogen storage disease type-II, it is a rare genetic disorder caused by deficiency in the enzyme acid alpha-glucosidase. This deficiency results in manifestations such as muscle weakness, delays in motor skills, bone complications and respiratory as well as cardiovascular issues. While there is presently no cure for Pompe disease, a common therapeutic approach is enzyme replacement therapy, which entails infusing the deficient enzyme to mitigate glycogen accumulation.
Duchenne muscular dystrophy
This is a genetic disorder characterised by muscle degeneration and weakness, resulting from mutations in the dystrophin protein, essential for maintaining muscle cell integrity. The primary symptom is muscle weakness, which can manifest as early as age two or three. This progressive condition often leads to mobility challenges and impacts various muscle groups, significantly affecting the individual’s quality of life.
Thalassemia
It is an inherited blood disorder that causes one’s body to have less haemoglobin than normal. The condition is caused by mutations in the DNA of cells that make haemoglobin. The cells are passed from parents to children. Diagnosis is simple with a blood test which reveals the number of red blood cells and abnormalities in size, shape or colour and it also analyses DNA to look for mutated genes. Inadequate haemoglobin production causes anaemia and potential symptoms like fatigue or breathlessness. Treatment involves blood transfusions and medications, with advancements leading to improved life expectancy and quality of life.
Haemophilia
Haemophilia is a rare genetic disorder marked by insufficient bloodclotting proteins, resulting in prolonged bleeding after injuries. Though minor cuts may not pose significant problems, individuals with severe haemophilia face the risk of life-threatening internal bleeding, especially in joints like knees, ankles and elbows. Diagnosis involves screening tests and clotting factor assessments, checking if blood clotting occurs properly. Treatment includes regular replacement of deficient clotting factors, while emerging therapies without clotting factors show promise. Early diagnosis and management play a vital role in mitigating potential complications associated with haemophilia.
Spinal muscular atrophy
Spinal muscular atrophy (SMA) is a genetic condition characterised by muscle weakness and atrophy. It can impact a child’s ability to crawl, walk, sit up and control head movements. A blood test can identify mutations or deletions in the SMN1 gene. Electromyography (EMG) assesses how muscles receive signals from nerves. While there is no complete cure for SMA, understanding its genetic basis has led to the development of treatment options, including gene replacement therapy like Zolgensma and drugs such as nusinersen (Spinraza) and risdiplam (Evyrsdi).