| 본문 : Purpose: To report a case of synergistic convergence with mild scoliosis, which was associated with a missense mutation (c.2887G>A ) in DCC (Deleted in colorectal cancer) gene.
Case summary: A 11-year-old female patient was referred to our clinic due to abnormal eye movement. On ophthalmic examination, her eye showed synergistic convergence with complete bilateral horizontal gaze palsy, absence of conjugate horizontal eye movements, with intact vertical gaze and convergence in both eyes. In primary position, the patient showed orthotropia at distance by alternate corver test and esotropia of 10 prism diopters(PD) at near. Her corrected visual acuity in both eyes was 20/20, anterior segment and fundus examination showed no abnormalities.
Orthopedic physical examination and radiologic evaluation demonstrated mild lumbar scoliosis. Brain MRI showed narrow atrophic mid pons, prominent inferior olivary nuclei, enlarged fourth ventricle which were radiologic findings suggestive of HGPPS (Horizontal Gaze Palsy with Progressive Scoliosis). Next-generation sequencing revealed a missens mutation c.2887G>A , p.(Val963Ile) on DCC gene was found, known as causing developmental split-brain syndrome (DSBS). No mutation was found in ROBO3 gene associated with HGPPS.
Conclusion: When a patient presents with synergistic convergence, orthopedic and radiologic evaluation could be helpful to diagnose, and also HGPPS(Horizontal Gaze Palsy with Progressive Scoliosis) associated with ROBO3 gene mutation and DSBS(Developmental split brain syndrome) associated with DCC(Deleted in colorectal cancer) gene should be considered in the differential diagnosis of synergistic convergence.
Currently, further research is required to understand differences in clinical presentations between HGPPS and DSBS. |