Views: 1,458 | Downloads:
21
| Responses: 0
| XML | Respond to this article | Alert & updates | Request permissions | Email to a friend |
Original ArticleOpen Access
A Thai Boy with Hereditary Enzymopenic Methemoglobinemia Type II
Shotelersuk V 
,
Tosukhowong P ,
Chotivitayatarakorn P ,
Pongpunlert W
,
Tosukhowong P ,
Chotivitayatarakorn P ,
Pongpunlert W Individuals with methemoglobin exceeding 1.5 g/dl have clinically obvious central
cyanosis. Hereditary methemoglobinemia is due either to autosomal dominant M hemoglobins
or to autosomal recessive enzymopenic methemoglobinemia. Four types of enzymopenic
methemoglobinemia have been described. In addition to methemoglobinemia, individuals with
type II, which is the generalized cytochrome b
5
reductase deficiency, have severe and progressive
neurological disabilities.
Here we report a 3-year-old Thai boy with type II hereditary enzymopenic methemo-
globinemia. He was born to a second-cousin couple. His central cyanosis was first observed around
10 months of age. His neurological abnormalities were seizures beginning at 1 year of age, micro-
cephaly, and inability to hold his head up. His cardiovascular and pulmonary evaluations were
unremarkable. Methemoglobin level by spectral absorption pattern was 18 per cent. A qualitative
enzymatic assay confirmed the deficiency of the cytochrome b
5
reductase enzyme. With this
definite diagnosis, a prenatal diagnosis for the next child of this couple will be possible.
Key word : Methemoglobinemia, Cytochrome b
5
Reductase
cyanosis. Hereditary methemoglobinemia is due either to autosomal dominant M hemoglobins
or to autosomal recessive enzymopenic methemoglobinemia. Four types of enzymopenic
methemoglobinemia have been described. In addition to methemoglobinemia, individuals with
type II, which is the generalized cytochrome b
5
reductase deficiency, have severe and progressive
neurological disabilities.
Here we report a 3-year-old Thai boy with type II hereditary enzymopenic methemo-
globinemia. He was born to a second-cousin couple. His central cyanosis was first observed around
10 months of age. His neurological abnormalities were seizures beginning at 1 year of age, micro-
cephaly, and inability to hold his head up. His cardiovascular and pulmonary evaluations were
unremarkable. Methemoglobin level by spectral absorption pattern was 18 per cent. A qualitative
enzymatic assay confirmed the deficiency of the cytochrome b
5
reductase enzyme. With this
definite diagnosis, a prenatal diagnosis for the next child of this couple will be possible.
Key word : Methemoglobinemia, Cytochrome b
5
Reductase
Download:
PDF