Case Report: From imaging to genetics: a case of congenital restrictive strabismus with SEOM expands the 22q11.2 duplication syndrome phenotype

TL;DR

A case report connects a rare eye condition with a genetic duplication, showing how imaging and genetics help diagnose and manage the condition.

Contribution

First reported association of a 22q11.2 duplication with SEOM-related restrictive strabismus.

Findings

MRI and OCT revealed the SEOM's posterior origin and mechanical effects on the eye.

A pathogenic 22q11.2 duplication was identified, expanding the syndrome's ocular phenotype.

Surgical risks and conservative management were emphasized due to SEOM location and prognosis.

Abstract

This study presents a case of restrictive strabismus with ipsilateral enophthalmos secondary to a supernumerary extraocular muscle (SEOM). Orbital MRI and posterior segment OCT provided direct imaging evidence that delineated the posterior origin of the SEOM and its mechanical traction on the globe, while also revealing concomitant hypoplasia of the medial and lateral rectus muscles. These findings together elucidate the mechanical basis of both ocular motility restriction and enophthalmos in this case. Genetic analysis revealed a pathogenic duplication in the 22q11.21 region, which—to our knowledge—is the first reported association linking this variant to SEOM-related restrictive strabismus, thereby expanding the ocular phenotypic spectrum of the 22q11.2 duplication syndrome. The discussion underscores that surgical intervention carries substantial risk due to the deep, optic-nerve-adjacent location of the SEOM and the presence of rectus muscle hypoplasia, compounded by the reportedly poorer prognosis associated with posterior SEOM (Type 3). Hence, conservative management was advised. This case highlights the central diagnostic role of MRI and offers novel insights into the etiology and individualized management of anomalous orbital structures.

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