Mitochondrial myopathy and sideroblastic anemia

Other Names: Myopathy with lactic acidosis and sideroblastic anemia; MLASA; Myopathy, lactic acidosis and sideroblastic anemia; Sideroblastic anemia and mitochondrial myopathy

Mitochondrial myopathy and sideroblastic anemia belongs to the heterogeneous family of metabolic myopathies. It is characterised by progressive exercise intolerance manifesting in childhood, onset of sideroblastic anaemia around adolescence, lactic acidaemia, and mitochondrial myopathy.

Epidemiology

Less than 10 cases have been described so far.

Cause

A 656C-->T mutation in the nuclear pseudouridine synthase 1 gene (PUS1), localised to 12q24.33, has recently been identified in some patients. Deficient pseudouridylation of mitochondrial tRNAs may be responsible for the oxidative phosphorylation disorder.

Inheritance

Autosomal recessive inheritance, a 25% chance

Transmission is autosomal recessive pattern.

Signs and symptoms

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed.

80%-99% of people have these symptoms

• Anemia(Low number of red blood cells or hemoglobin)
• Distichiasis
• EMG abnormality
• Generalized limb muscle atrophy(Generalized muscle wasting)
• High palate(Elevated palate)
• Lactic acidosis(Increased lactate in body)
• Long philtrum
• Micrognathia(Little lower jaw)
• Mitochondrial myopathy
• Muscular hypotonia(Low or weak muscle tone)
• Myopathy(Muscle tissue disease)

30%-79% of people have these symptoms

• Delayed puberty(Delayed pubertal development)
• Glaucoma
• Intellectual disability(Mental deficiency)
• Kyphosis(Hunched back)
• Microcephaly(Abnormally small skull)
• Scoliosis
• Short nose(Decreased length of nose)

Diagnosis

Muscle biopsy demonstrates low activity of complexes 1 and 4 of the respiratory chain and paracrystalline inclusions can be revealed in most mitochondria by electron microscopy.

NIH genetic and rare disease info

• NIH info on Mitochondrial myopathy and sideroblastic anemia

Mitochondrial myopathy and sideroblastic anemia is a rare disease.