Rare diseases

Rare diseases are often serious, chronic and life-threatening conditions. WHO defines a rare disease as often debilitating lifelong disease or disorder with a prevalence of 1 or less, per 1000 population. However, different countries have their definitions to suit their specific requirements and in the context of their population, the health care system and resources.

  • In the European Union, a disease is defined as rare when it affects fewer than 1 in 2,000 people (5 in 10,000 people). 
  • In the US, rare diseases are defined as a disease or condition that affects fewer than 200,000 patients in the country (6.4 in 10,000 people).
  • Japan identifies rare diseases as diseases with fewer than 50,000 prevalent cases (0.04%) in the country

However, in India the epidemiological data to define rare diseases in terms of prevalence rate are limited.  To overcome this, a hospital-based ‘National Registry for Rare Diseases’ has been initiated by ICMR by involving centers across the country that are involved in the diagnosis and management of rare diseases. A disease or disorder is defined rare in India when it affects fewer than 1 in 2500 individuals*.

There may be as many as 7,000 rare diseases, individual diseases may be rare, the total number of people with a rare disease is large.


  • 300 million people living with a rare disease worldwide
  • 72% of rare diseases are genetic
  • 70% of those genetic rare diseases start in childhood

To address various challenges in the management and research of rare diseases, a comprehensive “National Policy for Rare Diseases 2021” was approved by the Ministry of Health and Family Welfare, Government of India in March 2021.

Know more about:

The Indian Rare Disease Registry

National Policy for Rare Diseases, 2021










There are various causes of rare diseases, but still, the exact causes of many rare diseases are unknown. The common cause can be genetic, directly related with changes in genes or chromosomes. In some cases, genetic changes that cause disease are passed from one generation to the next. In other cases, genetic changes occur randomly in a person who is the first in a family with a rare disease.

Many rare diseases, including infections, some rare cancers and some autoimmune diseases are not inherited.





Early diagnosis of rare diseases is a challenge because of multiple factors that include lack of awareness among primary care physicians, lack of adequate screening and diagnostic facilities.

Delay in diagnosis or a wrong diagnosis increases the suffering of the patients. There is an immediate need to create awareness amongst the general public, patients & their families and training of doctors for early and accurate diagnosis, standardization of diagnostic modalities and development of newer diagnostic and therapeutic tools.




About 95% of rare diseases have no approved treatment even when a correct diagnosis is made. Where drugs are available, they are quite expensive as very few pharmaceutical companies globally manufacture drugs for rare diseases. For this reason, rare diseases are also called ‘orphan diseases’ and drugs to treat them are called “orphan drugs.

Reference https://main.mohfw.gov.in/sites/default/files/Final%20NPRD%2C%202021.pdf


The prevention of genetic disorders can be done at multiple levels.

Primary Prevention aims at preventing the occurrence of the disease, i.e., preventing the birth of an affected child. Though not always feasible, this strategy yields the highest returns in terms of decreasing the incidence & prevalence of rare disorders in the population in the long run.

Secondary prevention: This strategy focuses on avoiding the birth of the affected fetus (prenatal screening and prenatal diagnosis), early detection of the disorders, appropriate medical intervention to ameliorate or minimize the manifestations (newborn screening).

Tertiary prevention refers to the provision of better care and medical rehabilitation to those rare disease patients who present at an advanced stage of the disease.

Support from the Government of India:

The Ministry of Health and Family Welfare, Government of India initially formulated a National Policy for Treatment of Rare Diseases (NPTRD) in July 2017 and in 2021 the policy was revised as National Policy for Rare Diseases 2021.

The Rare Diseases Policy aims to lower the high cost of treatment for rare diseases with the increased focus on indigenous research and a National Consortium is to be set up with the Department of Health Research, Ministry of Health & Family Welfare as convener.

The Policy also focuses on early screening and prevention through primary and secondary health care infrastructure such as Health and Wellness Centres and District Early Intervention Centres (DEICs) and counselling for the high-risk parents. The screening will also be supported by Nidan Kendras set up by Department of Biotechnology.

The policy also aims to strengthen tertiary health care facilities for the prevention and treatment of rare diseases through designating 8 health facilities as Centre of Excellence(CoE). The CoEs will also be provided one-time financial support of up to Rs 5 crores for up-gradation of diagnostics facilities.                    

Under the policy, financial support up to Rs. 20 lakh under the umbrella scheme of Rashtriya Arogaya Nidhi is proposed by the Central Government for treatment, of those rare diseases that require a one-time treatment (diseases listed under Group 1)

State Governments can consider supporting patients of such rare diseases that can be managed with special diets or hormonal supplements or other relatively low-cost interventions (Diseases listed under Group 2).

The Policy also envisages a crowdfunding mechanism in which corporates and individuals will be encouraged to extend financial support through a robust IT platform for the treatment of rare diseases. Funds so collected will be utilized by Centres of Excellence for treatment of all three categories of rare diseases as the first charge and then the balance financial resources could also be used for research. 

The Central Government supports the state governments in implementing these strategies under the policy.

Know more about National Policy for Rare Diseases 2021







In India, rare diseases are categorized under the following groups.

Group 1: Disorders amenable to one-time curative treatment:

  1. Disorders amenable to treatment with Hematopoietic Stem Cell Transplantation (HSCT)
  2. Disorders amenable to organ transplantation

Group 2: Diseases requiring long term / lifelong treatment having relatively lower cost of treatment and benefit has been documented in the literature and annual or more frequent surveillance is required:

  1. Disorders managed with special dietary formulae or Food for special medical purposes (FSMP)
  2. Disorders that are amenable to other forms of therapy (hormone/ specific drugs)

Group 3: Diseases for which definitive treatment is available but challenges are to make the optimal patient selection for benefit, very high cost and lifelong therapy.

  1. Based on the literature sufficient evidence for good long-term outcomes exists for the given disorders
  2. For the following disorders for which the cost of treatment is very high and either long term follow up literature is awaited or has been done on a small number of patients




  • PUBLISHED DATE : Jun 28, 2021
  • CREATED / VALIDATED BY : Dr. Aruna Rastogi
  • LAST UPDATED ON : Jun 28, 2021


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