Complete LCAT deficiency is a disorder that primarily affects the eyes and kidneys.\n\nIn complete LCAT deficiency, the clear front surface of the eyes (the corneas) gradually becomes cloudy. The cloudiness, which generally first appears in early childhood, consists of small grayish dots of cholesterol (opacities) distributed across the corneas. Cholesterol is a waxy, fat-like substance that is produced in the body and obtained from foods that come from animals; it aids in many functions of the body but can become harmful in excessive amounts. As complete LCAT deficiency progresses, the corneal cloudiness worsens and can lead to severely impaired vision.\n\nPeople with complete LCAT deficiency often have kidney disease that begins in adolescence or early adulthood. The kidney problems get worse over time and may eventually lead to kidney failure. Individuals with this disorder also usually have a condition known as hemolytic anemia, in which red blood cells are broken down (undergo hemolysis) prematurely, resulting in a shortage of red blood cells (anemia). Anemia can cause pale skin, weakness, fatigue, and more serious complications.\n\nOther features of complete LCAT deficiency that occur in some affected individuals include enlargement of the liver (hepatomegaly), spleen (splenomegaly), or lymph nodes (lymphadenopathy) or an accumulation of fatty deposits on the artery walls (atherosclerosis).

Aldolase A deficiency is an autosomal recessive disorder associated with hereditary hemolytic anemia (Kishi et al., 1987).

The action myoclonus-renal failure syndrome, also known as progressive myclonic epilepsy-4 with or without renal failure (EPM4), is an autosomal recessive progressive myoclonic epilepsy associated with renal failure. Cognitive function is preserved (Badhwar et al., 2004). Some patients do not develop renal failure (Dibbens et al., 2009). For a discussion of genetic heterogeneity of progressive myoclonic epilepsy, see EPM1A (254800).

Triosephosphate isomerase deficiency (TPID) is an autosomal recessive multisystem disorder characterized by congenital hemolytic anemia, and progressive neuromuscular dysfunction beginning in early childhood. Many patients die from respiratory failure in childhood. The neurologic syndrome is variable, but usually includes lower motor neuron dysfunction with hypotonia, muscle weakness and atrophy, and hyporeflexia. Some patients may show additional signs such as dystonic posturing and/or spasticity. Laboratory studies show intracellular accumulation of dihydroxyacetone phosphate (DHAP), particularly in red blood cells (summary by Fermo et al., 2010).

Nonspherocytic haemolytic anaemia due to hexokinase deficiency is characterised by severe hemolysis, appearing in infancy. Seventeen affected families have been reported so far. Transmission is autosomal recessive. Mutations have been described in <i>HK1</i>, the gene that encodes red blood cell-specific hexokinase-R.

Combined methylmalonic aciduria (MMA) and homocystinuria is a genetically heterogeneous metabolic disorder of cobalamin (cbl; vitamin B12) metabolism, which is essential for hematologic and neurologic function. Biochemically, the defect causes decreased levels of the coenzymes adenosylcobalamin (AdoCbl) and methylcobalamin (MeCbl), which results in decreased activity of the respective enzymes methylmalonyl-CoA mutase (MUT; 609058) and methyltetrahydrofolate:homocysteine methyltransferase, also known as methionine synthase (MTR; 156570). The cblJ type is phenotypically and biochemically similar to the cblF type (MAHCF; 277380) (summary by Coelho et al., 2012).

Diamond-Blackfan anemia (DBA) is characterized by a profound normochromic and usually macrocytic anemia with normal leukocytes and platelets, congenital malformations in up to 50%, and growth deficiency in 30% of affected individuals. The hematologic complications occur in 90% of affected individuals during the first year of life. The phenotypic spectrum ranges from a mild form (e.g., mild anemia or no anemia with only subtle erythroid abnormalities, physical malformations without anemia) to a severe form of fetal anemia resulting in nonimmune hydrops fetalis. DBA is associated with an increased risk for acute myelogenous leukemia (AML), myelodysplastic syndrome (MDS), and solid tumors including osteogenic sarcoma.