Narcolepsy - HLA DNA Panel
| Order Code: | NARC |
| Epic Lab Code: | LAB3685 |
| Order Form: | A-1a Miscellaneous Request or Epic Req |
Commercial Mail-out Laboratory
6240 RCP
356-3527
6240 RCP
356-3527
Specimen:
Whole Blood
Collection Medium:
 |
| Pink top tube |
Minimum:
Preferred Minimum: 3 mL whole blood from pink top tube
Absolute Minimum: 1 mL whole blood from pink top tube
Absolute Minimum: 1 mL whole blood from pink top tube
Testing Schedule:
Time Varies
Analytic Time:
10 days upon receipt at reference laboratory
Reference Range:
By Report
Interpretive Data:
Background Information for Narcolepsy (HLA-DQB1*06:02)
Genotyping:
Characteristics: Narcolepsy is a sleep disorder associated with invalidating excessive daytime sleepiness and cataplexy (the sudden loss of muscle tone triggered by strong emotions). Additionally, disturbed nighttime sleep, sleep paralysis, and hypnagogic hallucinations (occurring in the period between sleep and wakefulness) are common.
Incidence: Narcolepsy affects approximately 1 in 2,000 individuals.
Cause: The HLA-DQB1*06:02 allele is strongly associated with narcolepsy, but, by itself, is not causative. Recent studies indicate HLA-DRB1*15 is no longer associated with narcolepsy.
Mutations Tested: HLA-DQB1*06:02 allele.
Clinical Sensitivity: 85-95 percent depending on ethnicity. Greater than 99 percent of affected Caucasians with cataplexy have the HLA-DQB1*06:02 allele.
Clinical Specificity: Less than 1 percent; 15-25 percent of unaffected Caucasians have the HLA-DQB1*06:02 allele.
Analytical Sensitivity and Specificity: 99 percent.
Characteristics: Narcolepsy is a sleep disorder associated with invalidating excessive daytime sleepiness and cataplexy (the sudden loss of muscle tone triggered by strong emotions). Additionally, disturbed nighttime sleep, sleep paralysis, and hypnagogic hallucinations (occurring in the period between sleep and wakefulness) are common.
Incidence: Narcolepsy affects approximately 1 in 2,000 individuals.
Cause: The HLA-DQB1*06:02 allele is strongly associated with narcolepsy, but, by itself, is not causative. Recent studies indicate HLA-DRB1*15 is no longer associated with narcolepsy.
Mutations Tested: HLA-DQB1*06:02 allele.
Clinical Sensitivity: 85-95 percent depending on ethnicity. Greater than 99 percent of affected Caucasians with cataplexy have the HLA-DQB1*06:02 allele.
Clinical Specificity: Less than 1 percent; 15-25 percent of unaffected Caucasians have the HLA-DQB1*06:02 allele.
Analytical Sensitivity and Specificity: 99 percent.
Test
Limitations:
This methodology will not differentiate between individuals who are
heterozygous (one copy) and those who are homozygous (two copies) for
the HLA-DQB1*06:02 allele. Rare diagnostic errors may occur due to
primer site mutations. Alleles other than HLA-DQB106:02 will not be
identified. Other genetic and non genetic factors that influence
narcolepsy are not evaluated.
Methodology:
Polymerase Chain Reaction/Fluorescence Monitoring
CPT Code:
83891, 83898; additional CPT code modifiers may be required for
procedures performed to test for oncologic or inherited disorders.