The Importance of Early Detection in Rare Genetic Disorders

Fabry disease is a rare lysosomal storage disorder that often goes undiagnosed for years due to its non-specific symptoms. A recent pilot program in Ninghai County, China, demonstrates the success of Fabry disease screening using a multi-step protocol. Researchers integrated dry blood spot (DBS) enzyme activity tests with globotriaosylsphingosine (Lyso-GL-3) measurements and genetic sequencing to identify patients. This approach specifically focused on the GLA IVS4 + 919G > A variant, which is a common late-onset mutation in East Asian populations.

Importance of Fabry Disease Screening in High-Risk Groups

Moreover, the study emphasizes that many carriers of the IVS4 variant remain asymptomatic for several decades. Consequently, clinicians must maintain a high index of suspicion in high-risk groups, such as those with unexplained hypertrophic cardiomyopathy or chronic kidney disease. Furthermore, the researchers utilized family pedigree analysis to detect additional cases among relatives of the index patients. In addition, they found that while enzyme activity is a useful initial indicator, genetic sequencing remains the gold standard for a definitive diagnosis.

Clinical Phenotypes and Genotype Analysis

Notably, the clinical manifestations of the IVS4 variant often involve progressive damage to the heart and kidneys later in life. Therefore, early detection through Fabry disease screening allows for timely clinical intervention and family counseling. In India, similar multicentric studies have shown that high-risk screening is a cost-effective strategy for identifying rare metabolic disorders. Similarly, these studies highlight a significant diagnostic delay of over a decade in many patients. As a result, implementing integrated screening programs can significantly improve patient outcomes by enabling earlier access to enzyme replacement therapy.

Frequently Asked Questions

How does the GLA IVS4+919G>A variant present clinically?

The GLA IVS4+919G>A variant is typically associated with a late-onset phenotype. It primarily affects the heart, often leading to hypertrophic cardiomyopathy, and the kidneys in the fourth to sixth decades of life.

Why is DBS enzyme activity screening alone insufficient for females?

Enzyme activity tests in dried blood spots often yield normal results in heterozygous females due to random X-chromosome inactivation. Therefore, molecular genetic sequencing is necessary to accurately identify female carriers.

What are the common high-risk groups for Fabry disease screening in India?

In India, high-risk screening is most effective among patients presenting with unexplained hypertrophic cardiomyopathy, idiopathic chronic renal failure, or cryptogenic stroke.

References

1. Ge Z et al. Successful experience with high-risk and family screening for Fabry disease in Ninghai County, Zhejiang Province, Eastern China: genotype‒phenotype analysis of the GLA IVS4 + 919G > A variant. BMC Med Genomics. 2026 Feb 05. doi: 10.1186/s12920-026-02314-9. PMID: 41645213.


2. Nampoothiri S et al. Fabry disease in India: A multicenter study of the clinical and mutation spectrum in 54 patients. JIMD Rep. 2020;54(1):82-93. doi: 10.1002/jmd2.12114.


3. Germain DP. Fabry disease. Orphanet J Rare Dis. 2010;5:30. doi: 10.1186/1750-1172-5-30.