Identification of Novel ARSA Mutations in Chinese Patients with Metachromatic Leukodystrophy

Objective. Metachromatic leukodystrophy (MLD) is an inherited disease caused by a deficiency of the enzyme arylsulfatase A (ARSA) that leads to severe physiologic and developmental problems. Our study is aimed at elucidating the clinical and genetic characteristics of Chinese MLD patients. Methods. Clinical data of 21 MLD patients was collected. All coding exons of ARSA and their flanking intronic sequences were amplified by polymerase chain reaction and subjected to direct sequencing. Results. All 21 patients were diagnosed with MLD clinically and genetically, out of which 17 patients were late infantile and 4 were juvenile types. A total of 34 ARSA mutations, including 28 novel mutations (22 missense, 1 splicing, 1 nonsense, 3 small insertions, and 1 small deletion mutation) and 6 known mutations (5 missense and 1 small insertion mutation), were identified. Prenatal diagnosis was performed for four pedigrees. One fetus was a patient, two fetuses were carriers, and two were wild type. Conclusions. The present study discovered 28 novel ARSA mutations and widely expanded the mutation spectrum of ARSA. Four successful prenatal diagnoses provided critical information for MLD families.