Probable assignment of soluble isocitrate dehydrogenase (IDH1) to 2q33.3

Abstract

Gene dosage effects for soluble isocitrate dehydrogenase (IDH1) were investigated in four unrelated cases with abnormalities involving the long arm of chromosome 2. Case 1 was trisomic for 2q33.3----qter, Case 2 monosomic for 2q33.3----q35, Case 3 trisomic for 2q11.2----q24.2, and Case 4 monosomic for 2q23----q24.2. These abnormalities were de novo except in Case 1, where trisomy 2q resulted from a maternal translocation. The red cell IDH1 levels were significantly reduced in Cases 1 (41.4% of normal value) and 2 (51.9%), while they were normal in Cases 3 and 4. The low IDH1 level also in the father of Case 1 (43.6%), together with the common electrophoretic phenotype of IDH1 in red cells as well as leukocytes, led us to suppose that Case 1 was really heterozygous for common and probable null alleles, and that the IDH1 gene locus could be excluded from 2q33.3----qter. On the other hand, normal IDH1 values in the parents of Case 2 were consistent with the hemizygosity for this locus in Case 2. The results suggested that the IDH1 locus could be assigned to the 2q33.3 band, especially the proximal portion of it.

Type and frequency of IDH1 and IDH2 mutations are related to astrocytic and oligodendroglial differentiation and age: a study of 1,010 diffuse gliomas

“…IDH1 on 2q33.3 encodes cytosolic NADP+ specific isocitrate dehydrogenase [13]. IDH1 is configured as a homodimer with two enzymatically active sites and most of its activity is detected in the cytosol and in peroxysomes [4].…”

Interstitial deletion of the long ARM of chromosome 2: A dose study on isocitrate dehydrogenase 1

“…4). In one patient of Narahara et al (1985) (Case a in Fig. 4), monosomy for 2q33.3-2q35 was observed and IDH1 level in the erythrocyte was reduced at about half of normal value.…”

“…4), monosomy for 2q33.3-2q35 was observed and IDH1 level in the erythrocyte was reduced at about half of normal value. Narahara et al (1985) speculated the IDH1 gene locus to be 2q33.3, although any clear evidence for excluding the possibility of 2q34-2q35 was not shown. Monosomy in our patient with reduced IDH1 activity is within a segment of 2q32.3 ~ 2q33.3 which shares a band 2q33.3 with the patient of Narahara et al (1985).…”

“…Narahara et al (1985) speculated the IDH1 gene locus to be 2q33.3, although any clear evidence for excluding the possibility of 2q34-2q35 was not shown. Monosomy in our patient with reduced IDH1 activity is within a segment of 2q32.3 ~ 2q33.3 which shares a band 2q33.3 with the patient of Narahara et al (1985). Therefore, it is most likely that the IDH1 gene is located within this segment.…”

Molecular Markers for Risk Stratification in Adult Acute Myeloid Leukemia with Normal Cytogenetics

“…Three classes of IDH isoenzymes exist in mammalian cells (two forms of mitochondrial IDH and cytosolic IDH). IDH1 gene is localized to chromosome band 2q33.3 and IDH2 gene to chromosome band 15q26.1 (Narahara et al,1985;Oh et al,1996). IDH2 encodes the mitochondrial isoform that uses nicotinamide adenine dinucleotide phosphate as a cofactor.…”