A Unique Interaction of IVS-I-1 (G>A) (HBA2: c.95+1G>A) with Hb Adana (HBA2: c.179G>A) Presenting as Transfusion-Dependent α-Thalassemia.
Hemoglobin
; 42(4): 247-251, 2018 Jul.
Article
em En
| MEDLINE
| ID: mdl-30623696
ABSTRACT
Nondeletional α-globin mutations are known to cause more serious clinical effects than deletional ones. A rare IVS-I-1 (G>A) (HBA2 c.95+1G>A) donor splice site mutation interferes with normal splicing of pre mRNA and results in activation of a cryptic splice site as well as a frameshift mutation. Hb Adana [HBA2 c.179G>A (or HBA1)] is a highly unstable variant hemoglobin (Hb) resulting from a mutation at codon 59 on the HBA2 or HBA1 gene, recognized to cause severe α-thalassemia (α-thal) syndromes. We report a unique case of compound heterozygosity for these two mutations in a 9-year-old boy who presented with a Hb level of 5.3 g/dL and hepatomegaly at the age of 15 months. He required regular blood transfusions in view of a Hb level of <7.0 g/dL and failure to thrive. He had thalassemic red cell indices and peripheral blood film. The Hb electrophoresis only showed a raised Hb F level (3.3%) and a pre run peak but the Hb H inclusion test was negative. His father had thalassemic red cell indices but a normal Hb level. His mother had almost normal Hb levels and red cell indices. Hb Adana involving the HBA2 gene was detected by mutiplex amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) in the proband and his father. DNA sequencing of the HBA2 gene confirmed the IVS-I-1 mutation in the proband and his mother. This case highlighted the unique interaction of the IVS-I-1 mutation with Hb Adana in a young Malay boy presenting with transfusion-dependent α-thal.
Palavras-chave
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Hemoglobina A2
/
Hemoglobinas Anormais
/
Talassemia alfa
Tipo de estudo:
Diagnostic_studies
Limite:
Child
/
Humans
/
Male
Idioma:
En
Revista:
Hemoglobin
Ano de publicação:
2018
Tipo de documento:
Article
País de afiliação:
Malásia