OBJECTIVETo analyze the relation between the genotype and phenotype in a Chinese patient with thalassemia intermedia and its implications for prenatal diagnosis and genetic counseling of thalassemia intermedia caused by co-existence of Hb H disease and beta; thalassemia major.

METHODSPhenotypic analysis was performed using standard hematological tests to measure red blood cell parameters and Hb concentration. Genotyping of beta thalassemia mutations and alpha thalassemia deletion were conducted using reverse dot-blot (RDB) assay and gap-PCR, respectively. We investigated the pathogenesis of this case by genotype-phenotype correlation analysis based on screening of the patient's family members. Prenatal diagnosis for a high-risk fetus in this family was performed by amniotic fluid DNA analysis.

RESULTSThe proband was identified as a patient with severe thalassemia intermedia caused by co-existence of Hb H disease (--(SEA)/-alpha (4.2)) and beta-thalassemia major (beta (CD17A)>T/beta (IVS2-654C)>T), whose father was heterozygous for beta thalassemia (beta (CD17A)>T/beta (N)) and alpha-thalassemia trait (--(SEA)/) and the heterozygous for beta thalassemia (beta (IVS2-654C)>T / beta (N)) and silent alpha-thalassemia (-alpha (4.2)/). The result of prenatal diagnosis showed co-existence of beta thalassemia major and silent alpha thalassemia in the high-risk fetus, and the parents requested termination of pregnancy after genetic counseling.

CONCLUSIONWe report for the first time a rare thalassemia intermedia case resulting from 4 complex alpha/beta thalassemia combination and the molecular pathogenesis of thalassemia intermedia is updated in the Chinese population. The practice of prenatal diagnosis in this case may also provide reference for diagnosis of similar cases.

Adult ; Child, Preschool ; China ; Female ; Genotype ; Humans ; Male ; Nucleic Acid Hybridization ; methods ; Phenotype ; Polymerase Chain Reaction ; methods ; Pregnancy ; Prenatal Diagnosis ; methods ; alpha-Thalassemia ; complications ; diagnosis ; genetics ; beta-Thalassemia ; complications ; diagnosis ; genetics

Mutation of the ATRX gene leads to X-linked alpha-thalassemia/mental retardation (ATR-X) syndrome and several other X-linked mental retardation syndromes. We report the first case of ATR-X syndrome documented here in Korea. A 32-month-old boy came in with irritability and fever. He showed dysmorphic features, mental retardation and epilepsy, so ATR-X syndrome was considered. Hemoglobin H inclusions in red blood cells supported the diagnosis and genetic studies confirmed it. Mutation analysis for our patient showed a point mutation of thymine to cytosine on the 9th exon in the ATRX gene, indicating that Trp(C), the 220th amino acid, was replaced by Ser(R). Furthermore, we investigated the same mutation in family members, and his mother and two sisters were found to be carriers.
Amino Acid Substitution ; Body Dysmorphic Disorders/complications ; Child, Preschool ; DNA Mutational Analysis ; Epilepsy/complications ; Exons ; Hemoglobin H/*genetics ; Humans ; Male ; Mental Retardation/complications ; Mental Retardation, X-Linked/complications/diagnosis/genetics ; Point Mutation ; Republic of Korea ; alpha-Thalassemia/complications/diagnosis/genetics