Our work in congenital conditions and rare diseases

A rare disease is defined as a condition which affects fewer than 1 in 2,000 people. There are between 6,000 and 8,000 known rare diseases, and approximately 80% of these are thought to have a genomic cause. Rare diseases are individually rare but collectively common, affecting one in 17 (or 3.5 million) people at some point in their lifetime. Although rare diseases can present at any age, approximately 75% affect children, and around 30% of children with a rare disease die before the age of five. Rare diseases can also present to virtually any medical speciality and often have highly variable clinical features, making diagnosis challenging.  As a result, many patients experience a prolonged ‘diagnostic odyssey’, involving multiple referrals, repeated investigations, misdiagnoses and significant delays before receiving an accurate diagnosis. This makes data collection difficult.

Congenital conditions are defined as a condition present at birth and includes structural and genomic conditions (including chromosomal and single-gene disorders). Some congenital conditions are detected during pregnancy, some are found at birth, while others are diagnosed only as a baby grows older. Around one in 50 babies are born with a congenital condition. Most congenital conditions are considered rare diseases.

The National Congenital Condition and Rare Disease Registration Service (NCARDRS), part of the National Disease Registration Service (NDRS) is a comprehensive registration service that collects, curates, quality assures and analyses data about people with rare and congenital conditions across the whole of England. We use a comprehensive, multi-source approach to data collection to ensure that rare and congenital conditions are identified as accurately and completely as possible. By bringing together information from a range of healthcare settings and data systems, we are able to build a robust national picture of these conditions and their outcomes.

How we enable population-level insight

We use the data we collect to provide national, population-level insights into rare and congenital conditions. This includes producing official statistics on the birth prevalence of congenital conditions and estimating how many people are living with specific rare diseases in England. By linking and following records over time, we can better understand long-term outcomes, survival and patterns of care across the lifetime of individuals affected with these conditions. These insights help clinicians, researchers and the NHS answer fundamental questions that are important to the patient and public such as ‘how many people have this condition? or ‘what happens to people with this condition over time?’ This ultimately helps to support improvements in diagnosis, care pathways, service planning and health outcomes.

How we support national screening programmes

NDRS has long-standing, collaborative relationships with several national screening programmes, including the NHS Fetal Anomaly Screening Programme (NHS FASP), the NHS Newborn Blood Spot Screening Programme (NHS NBS) and the NHS Sickle Cell and Thalassaemia screening programme (NHS SCT). By linking screening data with our registration data, we are able to provide independent, population-level evidence to help the screening programmes monitor, evaluate and improve screening for rare and congenital conditions. 

Find out more about how NDRS supports national screening programmes in the NHS.

Our registration system manages several national data feeds which are collated to make a full patient record by our registration staff. The data feeds include but are not restricted to:

1. Badgernet data - neonatal intensive care data.
2. Ultrasound system data - ultrasound reports from routine and non-routine ultrasounds where a congenital condition is suspected.
3. Specialised data – data from specialities and specialised units such as cardiology, which diagnose and treat congenital conditions and rare diseases.
4. Birth, treatment and death data – to help create a full patient record.
5. Germline molecular data - tests performed on individuals with a strong familial predisposition to conditions such as rare cancers.

Find out more about our work using genomics data to support disease diagnostics, prevention and treatment in the NHS.

Congenital conditions data collection process

The congenital conditions notifier process involves NHS teams collecting and submitting data on all pregnancy outcomes in England, including losses, terminations, stillbirths, and live births, regardless of gestation or age. Teams must notify suspected or confirmed congenital conditions by sending all relevant ultrasound reports including initial and follow-up information. 

Find out about the congenital conditions notifier process.

Rare Disease Data Set (RDDS)

In 2025, NDRS launched the Rare Disease Data Set (RDDS) a new national standard for collecting rare disease data in the NHS. 

Find out more about the RDDS and what data we collect. 

Patient self-registration

We understand that many people living with a rare condition would like to share their information with NDRS, and that being recognised and counted is important.

Following an  initial pilot period, we are reviewing the most appropriate and sustainable approach to support self-registration for rare diseases. We will provide further updates as this work progresses.

If you or someone you care for has a rare condition and would like to receive updates about opportunities to contribute information to NDRS, please subscribe to our email distribution list using the button above. We have also compiled a useful list of organisations and support services that may be able to offer further information and assistance.

Information for clinicians

If you are a clinician and you wish to report data to NDRS, please contact [email protected] for further information.

Rare disease registration in Northern Ireland, Scotland and Wales

NDRS collects data for people who live in England or who receive care in England. If you live outside England and are not treated in England, we are unable to collect your information.

However, the organisations and resources listed below may be able to provide further information about rare disease registration and support services in other parts of the UK and internationally.

• Northern Ireland - information for Northern Ireland residents can be found on the Northern Ireland Rare Disease Partnership website 
• Scotland - information for residents in Scotland can be found on the Public Health Scotland website 
• Wales - information about the Congenital Anomaly Register and Information Service for Wales (CARIS) can be found on the CARIS website

Patients can opt out of disease registration if they do not want us to hold or use their data. 

Find out how patients can request to opt out of the disease registration process.

NDRS produces a wide range of reports and publications using national registration data including annual data reports, data tables, briefings and peer reviewed articles in scientific journals. Our outputs provide reliable, evidence-based insights on the prevalence, outcomes and patterns of care for rare and congenital conditions, helping clinicians, researchers, policymakers and the public make informed decisions.

Key publications

The Congenital Condition Statistics report is produced on an annual basis and provides details of prevalence, timing of diagnosis and outcome, key public health indicators and more detailed information on congenital conditions detected in babies delivered in England including structural and genomic conditions such as Down’s syndrome, Edwards’ syndrome and Patau’s syndrome.

The Rare Conditions Registration Statistics provides prevalence estimates of rare conditions as a means of reporting information on the number of people known to be affected with certain rare conditions to a range of users.  This output continues to be expanded to include additional conditions as and when data collection allows.

NDRS contributes anonymised data to EUROCAT, the European Network of Population-Based Congenital Anomaly Registries. By pooling data across Europe, this collaboration enables robust international comparisons, shared expertise and strengthened public health surveillance. Data from

NDRS is combined with other member registries and published via the EUROCAT website, including prevalence rates (registration required), prenatal detection rates, key public health indicators such as perinatal mortality and terminations of pregnancy for fetal anomaly (TOPFA), and statistical monitoring of clusters and trends.

The National Fetal Anomaly Screening Programme (FASP) report is produced for NHS FASP programme monitoring and evaluation and provides national detection rates for Down's Syndrome, Edward's Syndrome and Patau's Syndrome from biochemistry screening tests, and a number of structural conditions screened for as part of the 20-week screening scan. 

Journal articles

NDRS has created an interactive journal library that lists numerous scientific journal publications produced by the National Disease Registration Service (NDRS) and demonstrates how we utilise patient data.

Explore the National Disease Registration Service (NDRS) scientific journal library.