Wednesday, June 20, 2018

ovalocytosis -

Ovalocytosis is one of the blood disorders characterized by red blood cells that are mostly elliptical (Palek & Lambert 1990). The term is also most often used to refer to blood disorders called South-East Asian ovalocytosis (SAO).

 More specifically, the characteristics of ovalocytosis are red oval and diameter red blood cells that contain hemoglobin. The midline will separate the pale area (the concave part) into 2 parts (O'Donnell et al. 1998). The ratio for his innovation is approximately longer: more than 1: 1 width and less than 2: 1.

SAO is commonly found in indigenous Melanesian and Malayan peoples, then extends further to Southeast Asia, such as Malaysia, Papua New Guinea, the Philippines and Indonesia (Liu et al., 1990, Jarolim et al. 1991, Jones et al., 1991, Schofield et al 1992, Takeshima et al., 1994).

Molecular studies found that the cause of SAO was a deletion in the 400th to 408th (27 bp) codon in the anion exchanger 1 (AE1) gene located on chromosome 17. The gene encoding this band 3 protein had a mutation in exon 11. Due to deletions on the codon, the 9 amino acids can not be expressed. The amino acids are: alanine (A), phenylalanine (F), serine (S), proline (P), glutamine (Q), valine (V), leucine (L), alanine (A), and alanine (A) . The loss of nine amino acids occurs at the boundary between the cytoplasmic domain and the first segment of transmembrane protein band 3 (Liu et al. 1990, Jarolim et al., 1991). According to Mohandas et al. (1992) in SAO patients, the resulting band 3 proteins increased cell membrane rigidity (decreased deformability). This possibility is due to the strong bonding of the ankirine to the mutated molecule.

SAO is derived autosomally dominant. The positive individuals of SAO are heterozygotes and until now the medical world and scientists have not found individuals with the homozygous gene. It is estimated that individuals with homozygous alleles for SAO are lethal (Jarolim et al., 1991, Liu et al., 1994, Allen et al., 1999). Until now, has not found the fact that SAO gives a harmful effect to the sufferer.