Special clinical features with a novel mutation site of CHN1 gene in a Chinese family with Duane retraction syndrome

ABSTRACT

Purpose

This study is to describe the special clinical and genotypic features of a Chinese family with variant types of Duane retraction syndrome and to present our experience on managing these cases.

Methods

Four individuals from one family were reviewed by ophthalmologic examinations, in which two affected and two unaffected individuals were revealed. MRI scans were performed on the two patients. Relevant gene mutations were screened by the next-generation sequencing technology and confirmed by Sanger sequencing technology.

Results

The six-year-old proband presented with special clinical features of severe horizontal gaze dysfunction, exotropia and mild scoliosis. His mother showed significantly limited binocular abductions, with retraction of eyeballs in adduction. From MRI scans, abducens nerves were not observed in both patients and the oculomotor nerve was slightly thin in the proband. The proband and his mother shared the same CHN1 gene mutation site (c. 62A>G; p.Y21C). Strabismus surgery was performed on the proband to correct the primary gaze exotropia.

(NM_001822: exon3 or NM_001025201: exon4: c. 62A>G; p.Y21C)

Conclusions

A novel CHN1 gene mutation was revealed from a Chinese family with Duane retraction syndrome. Remarkably, the proband and his mother presented different clinical features of ocular motility disorder. Strabismus correction surgery and amblyopia training helped to improve the appearance and visual function of the proband.

KEYWORDS:

• CHN1 gene
• Duane retraction syndrome
• horizontal gaze dysfunction

Acknowledgements

We are grateful to the patients and their family members for their participation in this study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by the Science and Technology Commission of Beijing Municipality Fund Project [Z171100000417039]. The funding body played no role in the design of the study and collection, analysis, and interpretation of data and in writing the manuscript.