Rare Condition Registration Statistics updated to 2022

The UK Rare Diseases Framework provides the following definition:

“A rare disease is defined as a condition which affects less than 1 in 2,000 people. It is currently estimated that there are over 7,000 rare diseases, with new conditions continually being identified as research advances. While 80% of rare diseases have an identified genetic origin, they can also be caused by disordered immunity, infections, allergies, deterioration of body tissues and organs or disruption to development while in the womb.

Although rare diseases are individually rare, they are collectively common, with 1 in 17 people being affected by a rare disease at some point in their lifetime. In the UK this amounts to over 3.5 million people.”

This is based on a consideration of data sources, clinical expertise, maturity of data pipelines, and our ability to benchmark data against similar information from other organisations.

Rare cancers are so designated because they have been extracted from the National Cancer Registration Dataset (see Data Sources section below) and defined as per the US National Cancer Institute’s Surveillance, Epidemiology and End Results (SEER) Program.

Congenital anomalies are defined as being present at delivery, likely originating before birth, and include structural, chromosomal and genetic conditions. Data are collected broadly in accordance with definitions and guidelines of the European Surveillance of Congenital Anomalies (EUROCAT). Congenital anomalies are coded using the International Classification of Disease version 10 (ICD-10) with British Paediatric Association (BPA) extension, which gives supplementary one-digit extensions to ICD-10 codes to allow greater specificity of coding. For more information about data collection, definitions and coding see the Technical details document which accompanies the NCARDRS Congenital Anomaly Statistics report. 

Consistent with international practice on prevalence reporting, only congenital anomalies in the following categories are included in this report:

• live births
• stillbirths
• late miscarriages between 20-23 completed weeks of gestation
• terminations at any gestation

In this report, for congenital anomalies baby/babies is used throughout to refer to all pregnancy outcomes; live births, stillbirths, late miscarriages between 20-23 complete weeks and terminations at any gestation regardless of their civil registration status.

The widely used definition of "prevalence" in congenital anomalies is a slightly different measure called "birth prevalence", since many congenital anomalies are identified during pregnancy. A measure of birth prevalence can be found in the NCARDRS Congenital Anomaly Statistics: Annual Data reports; what is presented here are point prevalence estimates.

For other rare conditions, the data are not based on either of these established registries and so have been obtained in different ways (see Data Sources section below).