title: [Molecular characterization of two new mutations of α° thalassemia in two Spanish families (mutation --(ED) and --(GP))].
abstract: OBJECTIVE
  The two structural genes encoding the human α-globin chains are located on the short arm of chromosome 16. Normal individuals have four genes α (αα/αα). α-thalassemias are usually produced by the deletion of one, two, three, or four α genes. Deletion of both α genes within the same chromosome (α° thalassemia) is commonly observed in individuals from the Mediterranean basin and Southeast Asia.
  
  
  METHODS
  We study two natural families of Madrid with microcytic hypochromic anemia. The DNA extracted from peripheral blood leukocytes was digested with different restriction enzymes and hybridization with probes of gene cluster α. The ends of the deletion were characterized by combining the techniques of Southern blot, PCR and FISH.
  
  
  RESULTS
  We present two new mutations of α° thalassemia in two Spanish families, not previously described in the literature. The deletion (--(ED)) is ∼80 kb with the break point 5' in the coordinate +100 (± 3 kb), whereas the end 3'HVR places in the coordinate 178±750 bp. The second deletion (--(GP)) is more extensive, with loss of 145 kb, placing the deletion in the end 5' between the coordinates 34 and 37, respecting therefore the telomere. In the centromeric region the breakpoint places as the previous one in the coordinate 178±1.4 bp.
  
  
  CONCLUSIONS
  In both mutations both alpha genes were deleted, the gene θ and the region HS40. The exact identification of these deletions is essential to determine the function of the genes α with a view to a possible genetic diagnosis.
authors: Servicio de Hematología, Hospital Clínico San Carlos, Universidad Complutense de Madrid, España. avillegas.hcsc@salud.madrid.org
authors: Ana
authors: A
authors: Villegas
authors: Paloma
authors: P
authors: Ropero
authors: Eduardo
authors: E
authors: Anguita
authors: Aurora
authors: A
authors: Hernández
authors: Marta
authors: M
authors: Polo
authors: Fernando
authors: F
authors: Ataúlfo González
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015139:Blotting, Southern; D002648:Child; D056905:Chromosome Breakpoints; D002885:Chromosomes, Human, Pair 16 / Q000235:genetics* / Q000648:ultrastructure; D005260:Female; D017353:Gene Deletion; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D013030:Spain / Q000453:epidemiology; D055542:alpha-Globins / Q000172:deficiency / Q000235:genetics*; D017085:alpha-Thalassemia / Q000453:epidemiology / Q000235:genetics*
chemical_list: D055542:alpha-Globins