Value of DNA testing in the diagnosis of sickle-cell anemia in childhood in an environment with a high prevalence of other causes of anemia.

BACKGROUND: Sickle-cell anemia (SCA) is the most common genetic disease worldwide caused by a single mutation in the gene HBB. DNA testing can help to clarify the diagnosis when Hb electrophoresis is inconclusive. We evaluated the usefulness and feasibility of DNA-based diagnosis of SCA in rural Central Africa. METHODS: This is a cross-sectional study conducted from November 2016 to end October 2017 in the Hôpital Saint Luc de Kisantu, located 120 km from Kinshasa. This hospital offers the management of SCA patients, mainly identified using the Sickling test (Emmel test) combined with clinical features. We included patients aged 6 months to 18 years locally diagnosed as SCA, and we collected clinical and hematological data. All patients were offered Hb electrophoresis and DNA testing at the Center for Human Genetics of the University of Kinshasa. RESULTS: This study included 160 patients. Hemoglobin capillary electrophoresis suggested that 136 (85%) were homozygote SS, 13 (8.1%) were heterozygote (AS), and 11 (6.9%) were homozygote normal (AA). DNA testing confirmed these electrophoresis findings, with the exception of four patients, two AS in electrophoresis were found SS due to recent transfusion, and two SS in electrophoresis were found AS because they have compound heterozygous form S/ß°-thalassemia. The diagnosis of SCA was therefore wrongly ascertained with Emmel test in 15% of patients. CONCLUSION: This study reveals a high proportion of false-positive SCA diagnoses in a rural environment in Central Africa. This underlines the importance of DNA testing in conjunction with Hb electrophoresis.

Dysmorphism and major anomalies are a main predictor of survival in newborns admitted to the neonatal intensive care unit in the Democratic Republic of Congo.

In Central-Africa, neonatal infections, asphyxia and prematurity are main reasons for admission to the neonatal intensive care unit and major determinants of newborn survival. Also, the outcome of newborns with congenital anomalies is expected to be poor, due to a lack of state-of-the art care. We conducted a study of 102 newborns recruited in the Neonatal Intensive Care Unit (NICU) at the University Hospitals of Kinshasa, DR Congo, to assess the impact of congenital anomalies. The presence of a major anomaly was associated with a hazard ratio of death of 13.2 (95%CI: 3.7-46.7, p < .001). In addition, the presence of three or more minor anomalies was associated with a 4.5-fold increased risk of death (95%CI: 1.1-18.6, p = .04). We conclude that like major anomalies, the presence of three or more minor anomalies should also be given particular attention and that the evaluation of dysmorphism should be promoted in NICU.

Morphological characterization of newborns in Kinshasa, DR Congo: Common variants, minor, and major anomalies.

The evaluation of minor physical variation is crucial in a dysmorphological examination. Currently, data on the spectrum and incidence of minor physical variants in Central African newborns is lacking. We therefore conducted a cross-sectional descriptive study of 722 newborns recruited within the first 24 hr of life, in two large maternities in Kinshasa, DR Congo. Minor anomalies were defined according to the series of articles in AJMG Part A and coded as human phenotype ontology terms. A total of 97 different morphological variants were recorded of which 13 were common. About 34.8% of the newborn carried one minor anomaly, 11.6% had two, and 4.3% had three minor anomalies. No gender differences were observed, but the incidence of specific anomalies appeared to vary with the geographical origin of parents within the DR Congo. The results of this study will aid clinicians to interpret morphological variation in Central African newborns.

Hydroxyurea treatment for adult sickle cell anemia patients in Kinshasa.

Background: Despite a high incidence of sickle cell anemia, hydroxyurea (HU) treatment is rarely used in the DR Congo. This study aims to assess the efficacy of HU, the incidence of side effects that may limit its use in adults and to determine the dose needed for clinical improvement in patients. Methods: In a prospective study, patients received an initial dose of 15 mg/kg/day which was increased by 5 mg/kg every 6 months, up to a maximum of 30 mg/kg/day. The response and side effects to HU were evaluated biologically and clinically every 3 months during a 2-year period. Results: Seventy adult patients with a moderate or severe clinical phenotype initiated treatment. Only minor side effects were reported. At the end of the 2-year treatment phase, 45 (64.3%) had dropped out, of whom 33 were without a clear reason. Clinical and biological improvement was more marked during the first year. There was a reduction in severe vaso-occlusive crises (p < 0.001), need for transfusion (p < 0.001), and hospitalization days (p = 0.038). Fetal hemoglobin (HbF) levels increased on average 2.9 times after 12 months (p < 0.001). The increase in mean corpuscular volume was greater in the first year (p < 0.001) than in the second year (p = 0.041). The decrease in leukocytes (p < 0.001) was significant during the first year. In 70% of patients, the 20 mg/kg/day dose was needed to reach the 20% HbF threshold. Conclusion: HU is effective and well tolerated. The magnitude of the response varies from one patient to another. Improvement of clinical manifestations is achieved in most patients with a relatively low dose. Effective implementation of HU treatment will require improved adherence to treatment.

Wolf-Hirschhorn Syndrome: Clinical and Genetic Data from a First Case Diagnosed in Central Africa.

Wolf-Hirschhorn syndrome (WHS) is a multiple congenital anomaly-intellectual disability syndrome caused by a deletion involving chromosome 4p16.3. We report clinical and genetic findings of the first WHS patient diagnosed in central Africa. This boy who presented with cleft palate, microcephaly, severe growth delay, and intellectual disability was 12 years old. Typical craniofacial features were present, though the characteristic "Greek helmet" appearance of the nose was less evident, probably reflecting a variable expression related to the genetic background. The clinical diagnosis of WHS was confirmed by array CGH, which revealed a terminal 4p16.3 deletion of 3.47 Mb, typically associated with a milder phenotype, contributing to the long survival of this child in a developing country.

Williams-Beuren syndrome: pitfalls for diagnosis in limited resources setting.

Patients with Williams-Beuren Syndrome can be recognized clinically, given the characteristic dysmorphism, intellectual disability, and behavior. We report on a Congolese boy with typical WBS facial characteristics. He suffered meningitis and coma at the age of 2 years then subsequently presented with profound intellectual disability and atypical behavior. The WBS was only made at age 8.2 years and confirmed with FISH testing and microarray-CGH. The present report aims to warn clinicians that infections may associate and/or modify a genetic disease as this may be observed in developing countries given the prevalence of infectious diseases.