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Ferreira TD, Freire AS, Silveira-Lacerda EP, García-Zapata MT
Rev Bras Hematol Hemoter. 2012;34(5):339-44
The objective of the present study was thus to evaluate
the effectiveness of genetic guidance and laboratory screening
of family members as educational and preventive measures in
respect to hemoglobinopathies in Goiás
Methods
After approval by the Human and Animal Research Ethics
Committee(CEPMHA)oftheHospitaldasClínicasoftheUniversidade
Federal deGoiás (HC-UFG), 77 patientswith hemoglobinopathies and
156 family members were enrolled at the UFG Hemoglobinopathy
Outpatient Clinic between June 2010 and June 2011 (Figure 1).
thereby assessing the respondent’s level of knowledge. It is important
to point out that the “education” variable may have influenced the
answers given in the second part of the interview. Therefore, the
educational level of the parents of children under 12 was considered
as they participated in the research.
After the interview, the carriers of hemoglobinopathies
received individualized genetic guidance in a suitable place to
safeguard the privacy of those involved. Using simple language,
a trained professional transmitted scientific information about
the disease, its course, its main clinical manifestations, the risk
of recurrence and measures used to prevent transmission. As
teaching materials in this educational process, small wooden
cubes with letters representing different hemoglobins on each
side were used as well as objects that simulated sickle-shaped
red blood cells, small and pale red blood cells, red blood cells
with hemoglobin C and unchanged red blood cells. In addition,
illustrative figures were presented to reinforce the concepts.
At the end of the guidance session, patients received written
material containing information about the aspects covered.
Three months after the genetic guidance session, patients with
hemoglobinopathies returned toHC-UFG for a cognitive assessment,
that is, their level of assimilated information was assessed (Appendix 2).
For this purpose patients answered hypothetical questions regarding
the likelihood of children being bornwith the disease according to the
parents’ genotype. The written cognitive evaluation was scored and
the result was compared with the level of knowledge demonstrated
before the guidance session.
The data obtained from the experimental part of the study
were entered into Microsoft Excel 2007 and analyzed using the
nonparametric Descartes’ Rule of Signs
(26)
.
Results
Table 1 shows the lab test confirmation of the patients’
diagnosis and the laboratory diagnosis of the family members.
Figure 1 - Methodological flowchart of the application of educational and
preventive measures
Enrollment
233 participants
156 family
members
77 hemoglobinopathy
carriers (patients)
Blood samples
Molecular Genetics
and Cytogenetics
Laboratory diagnosis/
confirmation of
diagnosis
Structured written
interview
Genetic guidance
Cognitive evaluation
(After three months)
Venous blood samples (4 mL) were collected from all
233 subjects in specific tubes containing the anticoagulant
ethylenediaminetetraacetic acid (EDTA). The biological material
was sent to the UFG Molecular Genetics and Cytogenetics
Laboratory (LGMC-UFG) to confirm the patients’ diagnosis and
to test other family members.
The laboratory investigation was performed using
selective and diagnostic tests such as the filter paper solubility
test
(20)
, osmotic resistance test in 0.36% saline
(21)
, erythrocyte
morphology
(22)
and alkaline electrophoresis in cellulose acetate at
pH 8.6
(23)
. Positive results were confirmed by acid electrophoresis
in agarose gel
(24)
; hemoglobin (Hb) A
2
(23)
was measured when the
beta thalassemia trait was suspected and intra-erythrocyte Hb H
testing was performed when electrophoresis was positive
(25)
.
The 77 patients with hemoglobinopathies (41 adults, 12 patients
between 12 and 17 who had their parents’ permission to participate
and the legal guardians of 24 patients under 12 years old) answered
a written interview divided into two parts (Appendix 1). The first
part included data about sociodemographic variables such as age,
nationality, place of residence, education, professional activity,
marital status and ethnic background. The second part consisted of
questions directly related to the concept and cause of the disease
under consideration, genetic inheritance, the difference between the
carrier of sickle cell trait and sickle cell anemia and genetic guidance
Table 1 - Laboratory confirmation of the diagnosis of hemoglobinopathy
carriers and laboratory diagnosis of family members
Patients (n = 77)
n (%)
No changes (Hb AA)
1 (1.3)
Increase in Hb F (Hb AA/
↑
F)
1 (1.3)
Sickle cell trait (Hb AS)
1 (1.3)
Hb CC disease
2 (2.6)
Hb SC disease
22 (28.6)
Sickle cell anemia (Hb SS)
42 (54.5)
Sickle cell anemia and increase in Hb F (Hb SS/
↑
F)
5 (6.5)
Sickle cell anemia and presence of Hb H (Hb SS/H)
3 (3.9)
Family members (n = 156)
n (%)
Sickle cell trait (HB AS)
79 (50.6)
Sickle cell trait and Hb H (Hb AS/H)
2 (1.3)
Hb C trait (Hb AC)
24 (15.4)
Presence of Hb H
1 (0.6)
Increase in Hb A2
1 (0.6)
Hb SC disease
3 (2.0)
Hb CC disease
1 (0.6)
No changes (Hb AA)
45 (28.9)
Hb: hemoglobin; Hb F: fetal hemoglobin;
↑
: increase