BACKGROUND: Lysosomal storage diseases (LSDs), a group of rare inherited metabolic disorders, result from specific lysosomal proteins deficiencies in the degradation of biomacromolecule, including over 70 different diseases, most of which are autosomal recessive. LSDs are multisystem disorders, and the clinical manifestations are usually broad and severe, involving the skeletal system, central nervous system (CNS), cardiovascular system, etc. Besides, patients with some subtypes of LSD have distinctive facial features.

MATERIAL AND METHODS: We performed next generation sequencing on 4 suspected mucopolysaccharidosis (MPS) cases to determine the genetic causes of the disease. By in vitro molecular cell assay, such as real-time polymerase chain reaction (RT-PCR) and western blot, we tested the pathogenicity of candidate variants.

RESULTS: We detected 5 novel mutations in 4 patients. The mutations were: c.211_214del and c.1270C>T in GUSB; c.1284+1C>A and c.2404C>T in GNPTAB; and c.717C>A in FUCA1). We identified a rare mucopolysaccharidosis VII patient, a rare fucosidosis patient, and 2 rare mucolipidosis II patients, one of which was an atypical patient. We also present a new pathogenic conjecture about a small deletion in GUSB.

CONCLUSIONS: Our study described rare diseases in Chinese patients and our results enrich the phenotype spectrum of related diseases, as well as mutation spectrum of related genes, which might be significant for clinical disease diagnosis and prenatal diagnosis.

Keywords: Fucosidosis, Lysosomal Storage Diseases, Mucolipidoses, Mucopolysaccharidosis VII, Base Sequence, Child, Child, Preschool, Fatal Outcome, Genetic Predisposition to Disease, Heterozygote, Homozygote, Infant, Mutation, Phenotype, Rare Diseases, Transferases (Other Substituted Phosphate Groups)