Anderson’s disease or chylomicron retention disease is a very rare genetic lipid malabsorption condition. Lipid malabsorption refers to the plasma lipid (HDL, LDL, and triglycerides) and fat-soluble vitamins particularly A and E. It is an autosomal recessively inherited disease with less than 50 cases having been reported in the world. The specific molecular defect was identified in 2003 and consists of mutations in the SAR1B gene which encodes for an intracellular Sar1b protein. Failure to thrive, growth failure, vitamin E deficiency and hepatic, neurologic and ophthalmologic complications are some of the characteristic features of this Anderson’s disease.
What Are The Symptoms of Anderson’s Disease?
Failure to thrive/grow is the first physical sign suggestive that a child is receiving inadequate nutrition for optimal growth and development. The signs and symptoms of Anderson’s disease or chylomicron retention disease appear in the first few months of life i.e. disease manifests in infancy or early childhood. Most of the symptoms are nonspecific symptoms. Chronic diarrhea, moderate growth retardation, digestive problems, and underweight are major symptoms of this disorder. This difficulty in fat absorption leads to excess fat in the feces. This condition is referred to as steatorrhea.
Neurological signs, including proprioceptive abnormalities, are flexia, tremor, ataxia and sensory myopathy, may occur severe in chylomicron retention disease. Neurological signs, although variable, most frequently cause a loss of reflexes. Recently, myolysis was reported in few patients with Anderson’s disease. Myolysis refers to the dissolution or liquefaction of muscular tissue. It is frequently preceded by degenerative changes such as infiltration of fat, atrophy, and fatty degeneration. Neuro-retinal manifestations are occasionally present in young patients. However, neurological signs may develop more frequently later in untreated individuals and consist most frequently of the loss of deep tendon reflexes.
This autosomal recessive disorder begins itself in infancy (less than 10 months), and although the clinical expression is variable, it is characterized by profound hypocholesterolemia, hypotriglyceridemia, lipid malabsorption, diarrhea, retinitis pigmentosa, acanthocytosis, and spinocerebellar degeneration. Infants presenting with failure to thrive and chronic diarrhea are usually associated with chylomicron retention disease. Acanthocytosis (appearance of thorn-like RBC) and retinitis pigmentosa (breakdown and loss of cells in the retina) are rarely observed in Anderson’s disease. A low-fat diet supplemented with lipid soluble vitamins (A and E) results in the resumption of normal growth with abatement of the gastrointestinal symptoms.
Ophthalmologic complications (minor visual abnormalities) are less severe in CRD than in other types of familial hypocholesterolemia. Cardiomyopathy and muscular manifestations have also been described. Essential fatty acid deficiency is especially severe early in life. Poor mineralization and delayed bone maturation can occur. Hepatic steatosis is common and hepatomegaly is reported to occur in about 20% of chylomicron retention disease patients. Although hepatic steatosis is a known complication of hypobetalipoproteinemia, in chylomicron retention disease it was detected in very few cases, and no cases of cirrhosis were reported.
Muscular ailments symptoms like muscular pain and cramps are described in some older patients with a delayed diagnosis. Perhaps as a consequence of malabsorption, malnutrition and vitamin D deficiency, these patients may complicate with poor mineralization and delayed bone maturation.
Anderson’s disease and/or Chylomicron retention disease is a hereditary syndrome that affects the absorption of dietary fats, cholesterol, and certain fat-soluble vitamins. It manifests in infancy or early childhood. Failure to thrive is the key physical sign and symptoms suggest that a child is malnourished. It appears in the first few months after birth and the syndrome is associated with chronic diarrhea, steatorrhea, neurologic complications, muscular complication, cardiomyopathy, growth retardation, hepatic steatosis, and ophthalmic complication. The disease follows an autosomal recessive pattern of inheritance.