# Levator muscle changes in Marcus Gunn jaw-winking syndrome and other forms of ocular congenital cranial dysinnervation disorder

## TL;DR

This study examines muscle changes in Marcus Gunn jaw-winking syndrome and related conditions, linking them to a shared neurological cause.

## Contribution

The study identifies histopathological similarities in levator muscle changes, suggesting a common neurogenic etiology for these disorders.

## Key findings

- Histopathological changes in levator muscles include fiber loss and atrophy.
- Marcus Gunn phenomenon and similar conditions share neurogenic muscle atrophy features.
- These findings suggest a common underlying cause related to cranial dysinnervation disorder.

## Abstract

This study was conducted to report the histopathological and clinical
features of the Marcus Gunn phenomenon and other similar conditions of upper
eyelid misfiring.

This was a retrospective study of patients with congenital ptosis with Marcus
Gunn phenomenon who have undergone surgical repair over a period of 12 years
and another two patients with upper eyelid misfiring in association with
extraocular movements to identify their histopathological findings as
subtypes representing ocular congenital cranial dysinnervation disorder.

Among 136 patients with congenital ptosis, 11 (8%) patients with Marcus Gunn
phenomenon or misfiring were identified, of whom 9 (6.6%) had typical known
Marcus Gunn phenomenon and 2 (1.4%) had eyelid misfiring similar to Marcus
Gunn phenomenon. In all patients, the histopathological changes of the
excised levator muscle included overall loss and/or atrophy of muscle fibers
and irregular-modified Gomori trichrome staining.

The Marcus Gunn phenomenon and similar misfiring conditions with synkinetic
extraocular muscle movements share findings that are consistent with the
neurogenic type of muscle atrophy. This result suggests a common underlying
etiology with variable clinical findings, representing the ocular
counterpart of congenital cranial dysinnervation disorder, which has been
reported as ocular congenital cranial dysinnervation disorder.