- Patient Preparation
- Lavender (EDTA) or pink (K2EDTA). Also acceptable: Yellow (ACD Solution A or B), lt. blue (sodium citrate), or green (sodium or lithium heparin).
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 1 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
Characteristics: HPFH is a clinically benign condition resulting from mutations within the beta globin gene cluster that alter normal hemoglobin switching and result in persistent production of hemoglobin F (Hb F). Individuals heterozygous for an HPFH deletion typically have elevated levels of Hb F with normal red blood cell indices, while homozygotes typically have Hb F levels approaching 100 percent and mild erythrocytosis. When an HPFH deletion is paired with another beta globin gene mutation, variable phenotypes can result.
Incidence: Varies depending on the population.
Cause: Beta globin gene cluster deletions and point mutations within the promoter of the gamma globin genes.
Mutations Tested: HPFH-1 (g.5174452_5259368del84917), HPFH-2 (g.5180404_5263982del83579), HPFH-3 (g.5215683_5265453del49771), HPFH-4 (g.5217940_5260078del42139), HPFH-5 (g.5246023_5258951del12929), HPFH-6 (g.5193975_5273259del79278), HPFH-7 (g.5247860_5270651del22792), and SEA-HPFH (g.5222878_5250288del27411).
Clinical Sensitivity: Unknown.
Methodology: Multiplex PCR and gel electrophoresis.
Analytic Sensitivity: Greater than 95 percent for the 8 targeted HPFH deletions.
Limitations: Only the 8 targeted deletions associated with HPFH will be interrogated. Point mutations or rare deletions that cause HPFH or delta/beta thalassemia will not be identified. Other genetic modifiers of Hb F levels will not be assessed. This test will not differentiate homozygosity for an HPFH deletion from an HPFH deletion paired with a rare globin gene cluster deletion. Diagnostic errors can occur due to rare sequence variations.
Counseling and informed consent are recommended for genetic testing. Consent forms are available online at www.aruplab.com.
See Compliance Statement C: www.aruplab.com/CS
|Component Test Code*||Component Chart Name|
|2005409||Hereditary Persistent Fetal Hb Specimen|
|2005412||Hereditary Persistant Fetal Hb Interp|