Lipid disorders and medications that disrupt fat soluble vitamin absorption/metabolism.

Table 4: Lipid disorders and medications that disrupt fat soluble vitamin absorption/metabolism.

Condition	Description	Lipid abnormality	Inheritance	Mutation	Testing	Clinical manifestations
Abetalipoproteinemia	Disrupts intracellular lipid transport in the intestine (chylomicrons) and liver (VLDL)	Absence of LDL and Very Low-Density Lipoprotein (VLDL)	Autosomal recessive	Microsomal Triglyceride Transfer Protein (MTP)	Lipid panel. Genetic testing available.	Affected infants may appear normal at birth, but by the first month of life, they develop steatorrhea, abdominal distention, and growth failure. Children develop retinitis pigmentosa and progressive ataxia, with death usually occurring by the third decade.
Familial hypobetalipoproteinemia	Abnormal apolipoprotein B	Low LDL	Autosomal codominant	apoB	Lipid panel, apoB. Genetic testing available.	Homozygotes present with fat malabsorption and low plasma cholesterol levels at a young age. They develop progressive neurologic degenerative disease, retinitis pigmentosa, and acanthocytosis, similar to patients with ABL.
Chylomicron retention disease	Impaired transport of chylomicrons within enterocytes	Lack of chylomicrons	Autosomal recessive	SAR1B	Postprandial lipid panel. Genetic testing available.	Failure to thrive; diarrhea; and steatorrhea. Other features of this disorder may develop later in childhood and often impair the function of the nervous system.
Smith-Limli-Opitz syndrome	Severe defect in cholesterol biosynthesis	Low LDL	Autosomal recessive	7-Dehydrocholesterol Reductase (DHCR7)	Elevated levels of the cholesterol precursor 7-dehydrocholesterol. Genetic testing available.	Growth failure; moderate-to-severe mental deficiency with variably altered muscle tone and dysmorphic features. Despite severe deficiency of normal bile acids, fat malabsorption and deficiencies of fat soluble vitamins are not common.
Lysosomal Acid Lipase Deficiency (LAL-D)	Lysosomal storage disorder	Elevated LDL-C and triglyceride, Decreased HDL-C	Autosomal recessive	LIPA	Enzymatic blood test for lysosomal acid lipase. Genetic testing available.	Hepatomegaly, hepatic steatosis, accelerated atherosclerosis, corneal arcus, xanthomas. Liver disease may progress to liver failure.
Cerebrotendinous xanthomatosis (CTX)	Disruption of bile acid production	Normal-to-low plasma cholesterol concentration	Autosomal recessive	CYP27A1	Elevated plasma and tissue levels of cholestanol. Genetic testing available.	Infantile-onset diarrhea, childhood-onset cataract, tendon xanthomas, and progressive neurologic dysfunction.