Table 2. Comparison of Diagnostic Yield by Disease-Specific Gene Panel or Broad Panel Testing Among Patients With Single Disease-Specific Diagnostic Indications.
| Referral indicationa | Total patients with referral indication, No. | Patients, No./total No. (%) | P valued | ||
|---|---|---|---|---|---|
| With positive results | With positive results for genes not on disease-specific panel | ||||
| Broad panel diagnostic yieldb | Disease-specific diagnostic yield (estimated)c | ||||
| Total patients, No. | 3147 | 689 | 614 | 75 | .02 |
| HCM | 1321 | 336/1321 (25.4) | 303/1321 (22.9) | 33/336 (9.8) | .13 |
| DCM | 869 | 166/869 (19.1) | 161/869 (18.5) | 5/166 (3.0) | .76 |
| ACM | 176 | 33/176 (18.8) | 28/176 (15.9) | 5/33 (15.2) | .48 |
| LVNC | 144 | 16/144 (11.1) | 2/144 (1.4) | 14/16 (87.5) | .001 |
| LQTS | 460 | 120/460 (26.1) | 106/460 (23.0) | 14/120 (11.7) | .28 |
| CPVT | 76 | 3/76 (3.9) | 2/76 (2.6) | 1/3 (33.3) | .65 |
| Brugada syndrome | 101 | 15/101 (14.9) | 12/101 (11.9) | 3/15 (20.0) | .54 |
Abbreviations: ACM, arrhythmogenic cardiomyopathy; CPVT, catecholaminergic polymorphic ventricular tachycardia; DCM, dilated cardiomyopathy; HCM, hypertrophic cardiomyopathy; LQTS, long QT syndrome; LVNC, left ventricular noncompaction cardiomyopathy.
Based on clinician complete test requisition form. Individuals with zero or multiple suspected or known diagnostic indications were excluded.
Positive results were defined as 1 pathogenic or likely pathogenic (P/LP) variant in a gene associated with an autosomal dominant or X-linked disease, 2 P/LP variants in the same gene associated with an autosomal recessive disease, or 1 P/LP variant and 1 variant of uncertain significance, each in a different copy of the same gene (ie, in trans) in a gene associated with autosomal recessive disease.
Results for each indication-specific panel are based on an estimation of actual testing results in the broad panel. The genes included in the broad panel are shown in eTable 1 in Supplement 1, and those included in each disease-specific panel are shown in eTable 2 in Supplement 1.
P values from significance testing for difference between broad testing yield and disease-specific testing yield. The significance threshold was P < .05.