used hydroxyurea, a chemotherapeutic agent which induces Hb F
production, at a dose of 10 mg/kg, in their patients assuming that since pathophysiology of Hb SD-Punjab is similar to Hb SS, increasing the level of Hb F
might decrease the vaso- occlusive events.8 However, Adekile A et al10 observed in all his 5 patients that Hb F
was around 20%, similar to our case.
A sample submitted for hemoglobin (Hb) evaluation on a 5-day-old premature male infant with intestinal perforation, intraventricular hemorrhage, anemia, and sepsis contained 61.1% Hb A2, 23.7% Hb F
, 2.1% Hb A2, and peaks of 8.2% and 5.2% in the P2 and P3 regions of the Bio-Rad Variant II HPLC [beta] thalassemia assay (Fig.
Its electrophoretic migration on both cellulose acetate (pH 8.4) and citrate agar (pH 6.2) was reported to be between Hb F
and Hb A, and that description persists in reference literature.
The most abundant adult form of Hb, [A.sub.0], consists of two [alpha] and two [beta]-chains ([[alpha].sub.2] [beta]2) and accounts for approximately 90% of Hb in hematologically normal adults and children over 6 months of age; (2) Hb [A.sub.2], ([[alpha].sub.2], [[delta].sub.2]) and Hb F
([[alpha].sub.2] [[gamma].sub.2]) constitute the other two minor components of Hb.
Hb A2 levels may be normal or increased while Hb F
levels are usually normal, although slightly increased in a few cases.
Hemoglobin variants and increases in circulating fetal hemoglobin (Hb F
),  (defined as an Hb F
level >2%) have been reported to interfere with some assay methods for [Hb A.sub.1c] (1-3).
In the healthy newborn, Hb F
(a2[gamma]2) is the major hemoglobin (~75%).
At the time it was assumed that the Hb F
of 15% was attributable to a combination of the patient's age and recovery from an oxidative haemolytic crisis.
The analysis revealed the absence of Hb A and the presence of sickle cell Hb (Hb S) (37.4%), along with normal Hb [A.sub.2] (3.2%) and Hb F
In the healthy neonate, fetal Hb, or Hb F
([[alpha].sub.2][[gamma].sub.2]), is the major species (~70%) (see Figure 1B).
An HPLC analysis revealed the following: Hb A, <I% (RI, >94%); Hb [A.sub.2],3.5% (RI, 2.0%-3.8%); Hb F
, 5.9% (RI, <2.0%); Hb S, 42.1% (RI, none); and Hb Other, 47.5% (RI, none).
The presence of [Hb.sup.var] or high Hb F
concentrations can be recognized by the separate elution of variant peaks or by abnormally high peaks on HPLC, and these abnormal findings arise mostly from genetic alterations in the globin genes (2,3).