Defects in biotin metabolism are mainly associated with either the enzyme Biotinidase or Holocarboxylase synthetase. Defects in either enzymes depletes biotin utilization by the cells. Holocarboxylase synthetase deficiency is an inherited disorder in which the body is unable to use the vitamin biotin effectively. This condition is inherited in an autosomal recessive pattern. We present a case of a 9 year old girl with atypical symptomology as a case holocarboxylase synthetase deficiency, who demonstrated an increased excretion of propionic and methyl malonic acids, with her biotinidase activity being normal. She demonstrated remarkable improvement on biotin supplementation.