Lowe syndrome (oculocerebrorenal syndrome of Lowe) is an X-linked recessive disorder caused by loss of functional mutation of the gene encoding OCRL1. The main clinical findings are congenital cataracts, mental retardation, and proximal renal tubule dysfunction (Fanconi syndrome). Various dental abnormalities have also been reported, mainly associated with rickets as a result of hypophosphatemia, one of the symptoms of Fanconi syndrome.We treated a 10-month-old boy with Lowe syndrome referred for examination of tooth mobility of erupted primary dentition. The primary central incisors had erupted in the mandible and no remarkable tooth deformity was detected. X-ray images revealed that root formation was not completed and the periodontal ligaments appeared to be slightly widened. However, disappearance of lamina dura and resorption of alveolar bone were not detected, which are usually associated with rickets. From these findings, it was difficult to evaluate whether the tooth mobility was abnormal or physiological. In addition, drug therapy had already been started for improving the metabolic defects associated with Fanconi syndrome, which was effective in preventing rickets and might explain why dental abnormalities were not clearly detected in this case. However, there is a risk of rickets-related dental abnormalities in the future as Fanconi syndrome worsens, thus long-term follow up and professional oral hygiene care are considered necessary in this case.