Types
The WHO International Working Group on Morphology of MDS (IWGM-MDS) defined three types of sideroblasts:
Type 1 sideroblasts: fewer than 5 siderotic granules in the cytoplasm
Type 2 sideroblasts: 5 or more siderotic granules, but not in a perinuclear distribution
Type 3 or ring sideroblasts: 5 or more granules in a perinuclear position, surrounding the nucleus or encompassing at least one third of the nuclear circumference.Type 1 and type 2 are found in non-sideroblastic anemias. Type 3 is found only in sideroblastic anemia. Symptoms and signs
Symptoms of sideroblastic anemia include skin paleness, fatigue, dizziness, and enlarged spleen and liver. Heart disease, liver damage, and kidney failure can result from iron buildup in these organs. Causes
Causes of sideroblastic anemia can be categorized into three groups: congenital sideroblastic anemia, acquired clonal sideroblastic anemia, and acquired reversible sideroblastic anemia. All cases involve dysfunctional heme synthesis or processing. This leads to granular deposition of iron in the mitochondria that form a ring around the nucleus of the developing red blood cell. Congenital forms often present with normocytic or microcytic anemia while acquired forms of sideroblastic anemia are often normocytic or macrocytic. Congenital sideroblastic anemia
X-linked sideroblastic anemia: This is the most common congenital cause of sideroblastic anemia and involves a defect in ALAS2, which is involved in the first step of heme synthesis. Although X-linked, approximately one third of patients are women due to skewed X-inactivation (lyonizations). Autosomal recessive sideroblastic anemia involves mutations in the SLC25A38 gene.
A pilar sheath acanthoma is a cutaneous condition most often found on the face, particularly above the upper lip in adults. : 675

See also
Dilated pore
Trichoadenoma
Skin lesion


== References ==