Holocarboxylase Synthetase Deficiency shows signs and symptoms that typically appear within the first few months of life, but the age of onset varies. Affected infants often have difficulty feeding, breathing problems, a skin rash, hair loss and a lack of energy. Immediate treatment and lifelong management with biotin supplements may prevent many of these complications. If left untreated, the disorder can lead to delayed development, seizures and coma. These medical problems may be life-threatening in some cases.