Diarrhoea with Acanthocytes in blood smear -
Ans. is 'c' i.e., Abetalipoproteinemia Abetalipoproteinemia: o Rare autosomal recessive disorder, o Affected individuals lack Beta lipoprotein hence its name. There is compleit abscence of all apo B containing lipoprotiens in the plasma (apo B 48 and apo B 100) where as HDL and apo AI concentration are approximately 50% of the normal. o The underlying cause of the abetalipoproteinemia is mutations in the senes encoding the microsomal trislvceride transfer protein MTP (microsomal triglyceride transfer protein). The protein is essential for the formation and eventual secretion of apolipoprotien B contaninig lipoproteins both from intestinal chylomicrons and liver. Microsomal triglyceride transfer protien normally facilitates association of lipid with apo B in the endoplasmic reticulum. In the presence of defective MTP this association fails to take place, as a result, no apo B containing lipoproteins are formed which accounts for their abscence in circulation. Chylomicrons formation is necessary' for the absorption and initial transport of fat soluble vitamins. The malabsorption of fat and the fat soluble vitamins that is typical of this condition is a result.of failure of chylomicron formation. The neurological manifestation of abelalipoproteinemias result from the inability to absorb and transport vitamin E. Vitamin A deficiency may also contribute to the retinal degeneration. Neuropathic changes affect post colum and spinocerebellar tract. Symptoms o Typically patients present in infancy' with failure to thrive and chronic diarrhoea' due to malabsorption. o Acanthocvtes' are seen on peripheral blood smear and an atypical retinitis pigmentosa on fundoscopy. o Later clinical manifestations include night blindness and neurological disability' particularly ataxia due to vitamin A and vitamin E deficiency'. Clinical features: o Chronic diarrhoea due to fat malabsorption (steatorrhoea). o Abdominal distension, o Failure to thrive. Neurological manifestation : o Clumsiness (first neurological maifestaiion) o Progressive ataxia o Neuropathy o Vision impairment o Retinitis pigmentosa o Impaired visual acuity' and visual field defects o Dysarthria o Sensory' motor neuropathy o Reflexes diminished or absent o Truncal and limb ataxia o Proprioceptive sensory' loss Laboratory and test findings : o Triglycerides level and cholesterol level are low. o Lipoprotein electrophoresis will reveal the absence of beta lipoproteins. o Acanthocy'tes constitute 50-90% of circulating red cell population. o Sensory nerve conduction studies have shown absent nerve action (SNAP s) or SNAPs of reduced amplitudes. Conduction velocities are usually normal, o Vitamin E levels are undetectable or very low. o Some patients develop elevated transaminases due to hepatic steatosis. o Homozygotes may have an impaired cortisol response to ACTH. Treatment o The neurological manifestations of abetalipoproteinemia can be prevented and at least partially reversed with the administration of vitamin E.
Whipples disease
Celiac sprue
Abetalipoproteinemia
Ulcerative colitis