Alpha-thalassemia mental retardation syndrome: A case report of two affected siblings

Abstract

Alpha-thalassemia mental retardation syndrome is an X-linked mental retardation (MR) syndrome characterized by a recognizable facial appearance, infantile hypotonia and cryptorchidism. Although the presence of alpha-thalassemia facilitates the diagnosis, its absence does not exclude the diagnosis of this rare syndrome. We describe two siblings who presented with facial dysmorphism, MR and a four-generation pedigree that revealed an X-linked recessive inheritance pattern. Their red blood cell indices were within the normal range; however, hemoglobin H inclusions were detected following cresyl blue staining on their peripheral blood film. Mutational analysis revealed a point mutation C7156T that is predicted to have caused a premature termination within the alpha-thalassemia MR syndrome gene in both siblings. Confirmation of this mutation has facilitated the process of genetic counseling, carrier testing and prenatal diagnosis amongst female relatives in this family.