Newborn screening for hemoglobinopathies at Muhimbili National Hospital, Dar es Salaam – Tanzania

Abstract

Background: Newborn screening (NBS) for hemoglobinopathies is important for the early detection and effective management of affected children.

Objectives: To determine the frequency of occurrence, types of, and factors associated with abnormal haemoglobins in newborns at Muhimbili National Hospital (MNH), Dar es Salaam.

Methods: A hospital-based, descriptive cross-sectional design was used to recruit newborns at Muhimbili National Hospital in 2009. Blood specimens were analyzed by High Performance Liquid Chromatography and alkaline Hb electrophoresis to determine the type and proportion of hemoglobin variants. Complete blood counts including red cell indices were done by automated hematology analyzer.

Results: Out of 2,053 samples analyzed, the prevalence of hemoglobinopathies was 18.2% (n=374). The percentages of children with defined hemoglobinopathies included 12.6% (n=258) with sickle cell trait (Hb FAS); 0.9% (n=19) as sickle cell carrier or Hb S Beta⁺ -thalassemia (Hb FSA); 0.54% (n=11) had SCA or Hb S Beta⁰-thalassemia (Hb FS); one Hb FA-D variant and 5.3% (n=109) with possibly α-thalassemia (Hb Bart’s). The frequency of occurrence of abnormal haemoglobins were highest among participants whose parental origin were Costal Regions, 35.6% (n=133) and Lake Zone, 10.2% (n=38). Participants from the Northern Region of Tanzania had the lowest frequency of occurrence, 6.7% (n=25) (X² = 37.7, p < 0.01). Having abnormal haemoglobins increased the likelihood of newborns being born at low gestational age (23.8%) by 1.5 fold as compared to newborns (16.3%) born without abnormal haemoglobins (X²=11.7, p=0.001).

Conclusions: The frequency of occurrence of abnormal hemoglobin is high and fulfills the World Health Organization (WHO) criteria of a disorder of public health significance. Therefore, newborn screening programme is highly recommended in Tanzania. The ethnic origin of the parents and the gestational age were significantly associated with occurrence of abnormal haemoglobins.

Keywords: Newborn screening, neonates , abnormal haemoglobins (Hemoglobinopathies), frequency of occurrence, High Performance Liquid Chromatography