Profil épidémiologique des hémoglobinopathies: étude transversale descriptive autour du cas index

Les hemoglobinopathies sont des affections constitutionnelles consequentes a des anomalies des hemoglobines. Elles sont souvent graves dans leurs formes majeures, leur prise en charge est lourde avec un grand impact psycho-social sur les patients et leur famille. Classees parmi les maladies rares, elles sont encore insuffisamment connues des professionnels de sante. Cette meconnaissance est a l'origine d'une errance diagnostique, d'un retard dans leur prise en charge et par consequent une morbidite et une mortalite elevee chez ces patients. L'Organisation Mondiale de la Sante (OMS) a publie en 2008 des donnees concernant l'epidemiologie des hemoglobinopathies: plus de 330000 cas naissent chaque annee avec une hemoglobinopathie (83% des cas de drepanocytose, 17% des cas de thalassemie). Les troubles de l'hemoglobine sont responsables d'environ 3,4% des deces chez les moins de 5 ans. A l'echelle mondiale, 7% environ des femmes enceintes seraient porteuses d'une forme de la thalassemie et 1% des couples sont a risque. Toutefois, elles sont relativement frequentes dans certaines regions du globe ou les mariages consanguins sont communs. Afin de decrire les caracteristiques epidemiologiques des familles a risque d'hemoglobinopathies (etude autour du cas) dont les cas index sont suivis au service de pediatrie a l'Hopital Provincial El Idrisi de Kenitra au Maroc, une etude transversale descriptive a ete realisee durant deux enquetes la premiere en mai 2015 et la deuxieme en juin de la meme annee lors des journees de vaccination des cas index contre le pneumocoque. Apres avoir recueilli les donnees epidemiologiques de nos patients, nous avons realise une etude biologique comportant: l'hemogramme avec etude morphologique des globules rouges en coloration MGG et numeration automatique des reticulocytes; les electrophoreses de l'hemoglobine a pH alcalin (8.8) et secondairement a pH acide (5.4) sur gel d'agarose avec integration densitometrique. 275 patients ont presente des profils compatibles a une hemoglobinopathie. La majorite de ces malades etaient issus de mariages consanguins (83.1%) et originaires de regions situees dans le nord du Maroc. L'enquete familiale a permis de retrouver les familles a risque, chez lesquelles on note une frequence elevee de drepanocytose. Nos resultats confirment l'existence de differents types d'hemoglobinopathies dans la population marocaine. Mots cles: Epidemiologie, thalassemies, drepanocytose, anemie, Kenitra, Maroc English Title: Epidemiological profile of hemoglobinopathies: a cross-sectional and descriptive index case study English Abstract Hemoglobinopathies are congenital disorders resultimg from hemoglobin abnormalities. Major forms are often severe, their management is difficult and associated with a great psychosocial impact on patients and their families. They are classified as rare diseases and are still insufficiently known by health professionals. This lack of knowledge is at the origin of diagnostic errors, delay in their management and therefore high morbidity and mortality rate for these patients. In 2008, the World Health Organization (WHO) has published data on hemoglobinopathies epidemiology: more than 330.000 cases of hemoglobinopathy occur each year (83% of cases of sickle cell anemia, 17 % of cases of thalassemia). Hemoglobin disorders are responsible for approximately 3.4% of deaths among people under the age of 5. At the global level, approximately 7% of pregnant women would be carriers of a form of thalassemia and 1% of couples are at risk. However, they are relatively frequent in some regions of the globe where consanguineous marriages are common. We conducted a descriptive cross-sectional study based on two surveys, the first in May 2015 and the second in June of the same year. It was performed in the immunization days to deliver pneumococcal vaccine to the index cases and it was aimed to describe the epidemiological features of families at risk of hemoglobinopathies (index case study), whose index cases were treated in the Department of Pediatrics at the Provincial Hospital El Idrisi, Kenitra, Morocco. After having collected the epidemiological data from patients, laboratory tests were performed including: blood count with red blood cells morphological assessment using the MGG assay and automatic numbering of reticulocytes; hemoglobin electrophoresis at alkaline pH (8.8) and then at acid pH (5.4) on agarose gel and densitometric integration. 275 patients had laboratory profiles compatible with hemoglobinopathy. The majority of these patients were born to consanguineous marriages (83.1%) and came from the north regions of Morocco. This family survey allowed to identify families at risk with a high frequency of sickle cell anemia. Our results confirm the existence of hemoglobinopathies variants among Moroccan population. Keywords: Epidemiology, thalassemias, sickle cell disease, anaemia, Kenitra, Morocco