Prevention of sickle cell disease: observations on females with the sickle cell trait from the Manchester project, Jamaica

Abstract

Screening for haemoglobin genotype was offered to senior school students in Manchester parish in south central Jamaica to test whether this knowledge would influence choice of partner and reduce births with sickle cell disease. Over six academic years, 15,539 students, aged mostly 15-19 years, were screened with voluntary compliance rising from 56 to 92 % over this period. All subjects were given permanent genotype cards and carriers of abnormal genes were offered counselling which explained the reproductive options but avoided recommendations. Prior to screening, all had been offered illustrated lectures on the genetics and clinical features of sickle cell disease. The current study, confined to females with the sickle cell trait, interviewed 763/845 (90.3 %) subjects seeking to assess retention of this knowledge and their response to subsequent boyfriends. Of those interviewed, 42 subjects were excluded (38 emigrated, one died, three received incorrect genotype cards) leaving 721 with complete information. Knowledge of genotype was retained in 95 %, the outcome of future offspring correctly recalled in 91 %, and haemoglobin genotype cards were still possessed by 89 %. A current 'boyfriend' was acknowledged in 403 (56 %) of whom the partner's genotype was known in 88 (74 determined by the project laboratory; 14 by other laboratories) and unknown in 315 (78 %). Offers of free blood tests to all these partners were accepted by only 14 (4 %). Seventeen (2.4 %) were married but the husbands genotype was known in only five (four AA, one AS) of these. Most subjects retain knowledge of their genotype and of its significance for having affected children but the reluctance of partners to be tested was a major obstacle.

Knowledge insufficient: the management of haemoglobin SC disease

“…Identifying couples at risk for having a child with HbSC enables pre‐conception counseling and diagnostic strategies, including pre‐implantation genetic testing, and post‐conception chorionic villus sampling or amniocentesis (Kuliev et al , ; Mason et al , ). Non‐invasive analysis of cell‐free fetal DNA extracted from maternal blood samples is an emerging technology for prenatal SCD diagnosis (Barrett et al , ; Perlado et al , ).…”

“…Primary care and emergency department clinicians should consider undiagnosed HbSC disease in children or adult patients presenting with complications such as priapism, hypersplenism and painful crises. Identifying couples at risk for having a child with HbSC enables pre-conception counseling and diagnostic strategies, including pre-implantation genetic testing, and post-conception chorionic villus sampling or amniocentesis (Kuliev et al, 2011;Mason et al, 2016). Non-invasive analysis of cell-free fetal DNA extracted from maternal blood samples is an emerging technology for prenatal SCD diagnosis (Barrett et al, 2012;Perlado et al, 2016).…”

Voluntary premarital screening to prevent sickle cell disease in Jamaica: does it work?

“…It was this lecture series that identified the need for genotype determination as a major request of the students. Specific interventions in the current project included illustrated lectures on the disease and its genetics offered at schools prior to screening, a , and phone interviews of students with the sickle cell trait 1-7 years later showed correct recall of genotype in 95% and of the genetics in 91% (Mason et al 2016b). …”

“…These 11 cases raise a series of issues but failure to discuss genetic information or refusal of the male partner to be tested accounted for seven cases and highlights the frailty of many Jamaican friendships where the girl does not wish to compromise a potential relationship by discussing a possibly contentious issue. The reason for Jamaican men declining to be tested may be fear of the result or the mild discomfort of a blood test, but only 14/315 (4%) male partners of students, known to carry abnormal genes, took advantage of a free blood test (Mason et al 2016b).…”

“…Completeness of dataset It was assumed that the databases derived from the 12 hospitals covered the great majority of deliveries in screened students, and this was supported when interviews with 200 AS mothers confirmed that over 95% deliveries occurred in these hospitals (Mason et al 2016b). …”