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Idiopathic dilated cardiomyopathy: familial prevalence and HLA distribution
C J McKenna1, M B Codd, H A McCann
1Department of Clinical Cardiology, Mater Misericordiac Hospital (University College), Dublin, Ireland.
Insights
Familial dilated cardiomyopathy shows a predisposition linked to Human Leukocyte Antigen (HLA) type DR4. This specific HLA subtype was significantly more prevalent in familial cases, suggesting its role in identifying at-risk families.
Area of Science:
- Cardiovascular Genetics
- Immunogenetics
Background:
- Dilated cardiomyopathy (DCM) is a significant cause of heart failure.
- Identifying genetic predispositions, particularly in familial cases, is crucial for early screening and intervention.
- Human Leukocyte Antigen (HLA) associations with cardiovascular diseases are increasingly recognized.
Purpose of the Study:
- To investigate the distribution of HLA alleles in familial versus non-familial dilated cardiomyopathy.
- To determine if specific HLA types are associated with an increased risk of developing familial DCM.
- To explore the potential of HLA profiling as a screening tool for families at risk of DCM.
Main Methods:
- Compared HLA profiles of 100 DCM patients (including familial and non-familial subgroups) with 9000 healthy controls.
- Screened 200 first-degree relatives from 56 proband families for DCM using echocardiography.
- Analyzed HLA-DR4 subtype frequencies in familial and non-familial DCM probands.
Main Results:
- Familial DCM was identified in 25% (definite) to 45% (possible) of the studied families.
- HLA-DR4 frequency was similar between all DCM patients and controls (39% vs. 32%).
- Significantly higher prevalence of the HLA-DR4 subtype was observed in familial DCM probands (68%) compared to non-familial DCM probands (32%, P < 0.05).
Conclusions:
- Findings support an HLA-linked genetic predisposition to familial dilated cardiomyopathy.
- The HLA-DR4 subtype is significantly more common in familial DCM cases.
- The HLA-DR4 haplotype is associated with a substantial proportion of families at risk for dilated cardiomyopathy, highlighting its potential as a biomarker.
Objectives:
To compare HLA distribution in familial and non-familial dilated cardiomyopathy, because a serum marker that could identify families at risk of developing dilated cardiomyopathy should be of use in screening for the disease.
Patients:
100 patients with dilated cardiomyopathy.
Methods:
200 first degree relatives from 56 of the proband families were screened for dilated cardiomyopathy by echocardiography. The HLA profile of the patients with dilated cardiomyopathy, as well as of the familial and non-familial subgroups, was compared with that of 9000 normal controls.
Results:
The familial prevalence of dilated cardiomyopathy in this patient group was "definite" in 14 of 56 (25%) and "possible" in 25 of 56 (45%). The HLA-DR4 frequency in the 100 patients with dilated cardiomyopathy was similar to that in the 9000 controls (39% v 32%). However, the DR4 subtype was significantly more common in the 25 probands with a familial tendency to dilated cardiomyopathy than in the 31 probands with non-familial dilated cardiomyopathy (68% v 32%; P < 0.05).
Conclusions:
The present finding supports an HLA linked predisposition to familial dilated cardiomyopathy. The HLA type DR4 was significantly more common in familial than in non-familial cases. The DR4 halotype was associated with two thirds of the families at risk for dilated cardiomyopathy.