National Thalassemia Registry: A 30-year Journey of implementing Carrier Screening in Singapore

Introduction

Haemoglobinopathies, which include thalassemia and structural haemoglobin variants, are the most common inherited disease affecting an estimated 20% of the world’s population. Globally, ∼300,000 children are born annually with haemoglobinopathies, making it the most clinically significant monogenic disorder. It is estimated that thalassemia contributes to approximately 3.4% of deaths in children under 5 years. Thalassemia poses a significant economic cost globally, with estimated per patient care cost of $128,000 annually.

In 1972, World Health Organization (WHO) described the development of computerized genetic registers for genetic disorders,⁴ which would facilitate testing to detect healthy carriers, offer subsequent cascade screening, pre-natal counselling and diagnosis in at-risk carrier couples of the associated risk and options available in management of subsequent pregnancies/affected pregnancies. Thalassemia is one such disorder where healthy carriers can be easily identified by simple, inexpensive and accurate blood tests.

National Thalassemia Registry

The National Thalassaemia Registry (NTR) is a registry established in Singapore since 1992, with the aim of registering all Singaporeans with thalassaemia and haemoglobinopathies. The NTR provides government subsidised screening for all first-degree relatives and genetic counselling to patients and their families with thalassemia.

Since the creation of the NTR, to date (as of 30 June 2023) there are 81,484 registrants in the registry, with 105 cases of thalassaemia major registered since between 1992 and 2019. The NTR’s 30-year history describes a successful model of a genetic registry and provides a record of how thalassemia’s prevalence within the nation has evolved over the years.