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.

Keywords

Alpha-thalassemia mental retardation syndrome (ATR-X) gene - X-linked mental retardation