[Family screening for HBB*S gene and detection of new cases of sickle cell trait in Northeastern Brazil].
OBJECTIVE
To estimate the additional number of affected individuals based on the prevalence of sickle-cell syndromes among relatives of index cases.


METHODS
Cross-sectional study of relatives of a random sample of index cases identified through a neonatal screening program in Northeastern Brazil, between 2001 and 2005. The extended family trial model included 463 relatives of 21 index cases. Relatives were classified as nuclear family (NF: father, mother, and siblings); first degree extended family (N1: grandparents, uncles and aunts, and first cousins); second degree extended family (N2: children of first cousins); extended family (NA: NF+N1+N2); and extended nuclear family (NA1: NF+N1). The presence of HBB*S and other abnormal hemoglobins was confirmed by high-performance liquid chromatography. The association between the presence of HBB*S and other variables was calculated using prevalence ratios and their respective 95% confidence intervals, and differences between means were calculated using Student's t test with a 5% significance level.


RESULTS
Of relatives, 81% had no knowledge of sickle-cell anemia and HBB*S was present in 114 family members. A total of 53.3% of the studied population was considered as of reproductive age, and 80% of HBB*S carriers had already had children. Frequency was higher among NF (69%), but was also high in N1 (22.8%). NA1 screening resulted in the detection of 69 carriers additional (a 172% increase).


CONCLUSIONS
These results indicate that family screening for the identification of sickle-cell carriers should be extended to first degree relatives.
Bandeira
Flavia Miranda Gomes C
FM
Fundação de Hematologia e Hemoterapia de Pernambuco, Recife, PE, Brazil.
Santos
Magnun Nueldo Nunes
MN
Bezerra
Marcos André M
MA
Gomes
Yara M
YM
Araujo
Aderson Silva
AS
Braga
Maria Cynthia
MC
Souza
Wayner Vieira
WV
Abath
Frederico G C
FG
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid; D003430:Cross-Sectional Studies; D005190:Family; D005260:Female; D006451:Hemoglobin, Sickle / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D015995:Prevalence; D012805:Sickle Cell Trait / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics
D006451:Hemoglobin, Sickle