Clinical and genetic characteristics of Chinese patients with congenital fibrosis of the extraocular muscles.

OBJECTIVE: This study aimed to describe the clinical and genetic characteristics of Chinese patients with congenital fibrosis of the extraocular muscles (CFEOM), and to evaluate the phenotype-genotype correlations in these patients. METHODS: This was a retrospective study. Patients with CFEOM underwent detailed ophthalmic examinations and magnetic resonance imaging (MRI). Panel-based next-generation sequencing was performed to identify pathogenic variants of disease-causing genes. RESULTS: Sixty-two patients with CFEOM were recruited into this study. Thirty-nine patients were diagnosed with CFEOM1 and 23 with CFEOM3. Forty-nine of the 62 patients with CFEOM carried either KIF21A (41/49) or TUBB3 variants (8/49). Six known missense variants in the KIF21A and TUBB3 genes, and a novel variant (c.3906T > A, p.D1302E) in the KIF21A gene were detected. Most patients with CFEOM1 carrying the KIF21A mutation displayed isolated CFEOM, whereas patients with CFEOM3 carrying the TUBB3 mutation had a wide range of clinical manifestations, either CFEOM alone or syndromes. Nystagmus was also present in 12 patients with CFEOM. Furthermore, the MRI findings varied, ranging from attenuation of the extraocular muscles to dysgenesis of the cranial nerves and brain structure. CONCLUSIONS: The novel variants identified in this study will further expand the spectrum of pathogenic variants in CFEOM-related genes. However, no phenotype-genotype correlations were established because of the diversity of the clinical characteristics of these patients.

Horizontal gaze palsy with progressive scoliosis: Further expanding the ROBO3 spectrum.

OBJECTIVE: Horizontal gaze palsy with progressive scoliosis (HGPPS) is a rare, autosomal recessive disorder resulting from axonal midline crossing defect due to variants in ROBO3. METHODS: We retrospectively evaluated demographics, clinical phenotype, course of spinal deformities, and neuroimaging findings of six Turkish patients with HGPPS. We performed targeted gene testing by next-generation sequencing. RESULTS: The median age at symptom onset and diagnosis was 1.5 years (0.5-4), and 11 years (2-16), respectively. Oculomotor signs were the most common presenting symptom (n = 4), followed by scoliosis (n = 2). The course of scoliosis was progressive and accompanied by kyphosis, showed intrafamilial variability, and was corrected surgically in three of the patients. Intellectual disability (n = 4), hypergonadotropic hypogonadism (n = 2), hearing loss (n = 2), and tranisent movement disorders (n = 1) were additional features. Targeted gene sequencing revealed five distinct homozygous variants. Of the four novel variants, two of them were located in the acceptor site of the noncoding region of the gene, remaining two were missense and frameshift variants, located in immunoglobulin-like domain-2, and cytoplasmic signaling motif 2, respectively. Structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) showed the absence of decussation of superior cerebellar peduncle and dorsal transverse pontine fibers. INTERPRETATION: Spectrum of HGPPS is further expanded with novel variants in the ROBO3 with clinical and radiological fingerprints. Spinal deformities require close orthopedic screening and individualized approach. Intellectual disability and hearing loss emerge as additional features. Hypogonadism and transient subtle movement disorders require further attention and confirmation from other series.

Congenital cranial dysinnervation disorder with homozygous KIF26A variant.

Congenital fibrosis of the extraocular muscles (CFEOM) type 1 is associated with heterozygous missense variants in KIF21A, which encodes a kinesin-like motor protein. Individuals with CFEOM1 have severe paralysis of upgaze and ptosis, resulting in a pronounced chin-up head posture. There can also be limitations of horizontal eye movements. Loss of function of KIF26A, an unconventional kinesin motor protein that lacks ATP-dependent motor activity, has been recently reported to cause a spectrum of congenital brain malformations associated with defects in migration, localization, and growth of excitatory neurons. It has also been associated with megacolon resembling Hirschsprung's disease. We report the case of a boy with homozygous loss of function of KIF26A with restricted eye movements, specifically restricted upgaze and downgaze with variable nystagmus and dissociated vertical eye movements. This case represents a congenital cranial dysinnervation disorder, most similar to CFEOM, and is the first report of a congenital cranial dysinnervation disorder caused by a kinesin other than KIF21A.

MRI evaluation of cranial nerve abnormalities and extraocular muscle fibrosis in duane retraction syndrome and congenital extraocular muscle fibrosis.

PURPOSE: To investigate the alterations in extraocular muscles (EOMs) by magnetic resonance imaging (MRI) among patients diagnosed with Duane retraction yndrome (DRS) and congenital fibrosis of the extraocular muscles (CFEOM), who present with various cranial nerve anomalies in an attempt to enhance the clinical diagnostic process. METHODS: A case-control study was conducted to evaluate 27 patients with DRS and 14 patients with CFEOM. All patients underwent MRI scans of the brainstem and orbital examination. Neurodevelopmental assessments were conducted through MRI, and maximum cross-sectional area and volumes of EOMs were obtained. Three types of models were constructed using machine learning decision tree algorithms based on EOMs to predict disease diagnosis, cranial nerve abnormalities, and clinical subtypes. RESULTS: Patients with bilateral CN VI abnormalities had smaller volumes of LR, MR, and IR muscles compared to those with unilateral involvement (P < 0.05). Similarly, patients with CFEOM and unilateral third cranial nerve abnormalities had a smaller maximum cross-section of the affected eye's SR compared to the contralateral eye (P < 0.05). In patients with both CN III and CN VI abnormalities, the volume of SR was smaller than in patients with CN III abnormalities alone (P < 0.05). The prediction model using EOMs volume showed a diagnostic precision of 82.5% for clinical cases and 60.1% for predicting cranial nerve abnormalities. Nonetheless, the precision for identifying clinical subtypes was relatively modest, at only 41.7%. CONCLUSION: The distinctive volumetric alterations in EOMs among individuals exhibiting distinct cranial nerve anomalies associated with DRS or CFEOM provide valuable diagnostic insights into to Congenital Cranial Neurodevelopmental Disorders (CCDDs). MRI analysis of EOMs should thus be regarded as a crucial diagnostic modality.

Orbital Fibrotic Band as Cause of Monocular Elevation Deficiency.

Monocular elevation deficiency is a congenital, unilateral inability of elevation. It is classified as innervational, restrictive, or combine types. Here, we report a rare case of monocular elevation deficiency who had 60 PD left hypotropia and left ptosis with limited elevation (-5) both on abduction and adduction. Orbital MRI revealed a hypointense fibrotic band between the superior oblique and superior rectus muscles extending obliquely in the superonasal direction between the sclera and orbital roof. She was successfully treated after severing the fibrotic band between the sclera and bony orbit.

Marcus-Gunn jaw winking syndrome: case series study and management algorithm.

PURPOSE: To identify a rationale for treatment of patients with Marcus Gunn jaw winking syndrome (MGJWS). METHODS: Retrospective review of 38 consecutive patients with MGJWS referred to a single tertiary institution. Clinical data included visual acuity, ocular motility, side of jaw-wink, presence or absence of ptosis, levator function, clinical photographs, and management undertaken. Thirty-two patients were operated on with customized surgery by a senior surgeon (FQL). RESULTS: Cases with no ptosis or mild ptosis were managed conservatively. Levator advancement (LA) was successful in case of moderate ptosis and negligible synkynesis but resulted in a more evident synkinesis. Levator resection (LR) in patients with severe ptosis was associated with high rate of ptosis recurrence. Ptosis was adequately corrected in all patients submitted to uni- or bilateral levator excision (LE) and bilateral frontalis suspension (FS) or unilateral frontalis flap (FF). Jaw winking resolved in all patients submitted to LE but recurred in three cases at a later stage. Strabismus surgery was performed simultaneously in case of associated esotropia or hypotropia. CONCLUSIONS: Moderate ptosis can be corrected with LA, but success is not related to levator function and synkinesis becomes more evident postoperatively. In severe ptosis, LR showed unpredictable results. In case of severe ptosis and severe synkinesis, uni- or bilateral LE and bilateral FS are recommended; unilateral FF is an alternative in patients who refuse bilateral treatment, as the cosmetic outcome is usually better than after unilateral FS.

Echoencephalography of Möbius sequence: A congenital cranial dysinnervation disorder with brainstem calcifications.

BACKGROUND AND PURPOSE: Möbius sequence (MBS) previously known as Möbius syndrome is a rare nonprogressive developmental defect of the rhombencephalon leading to congenital abducens (VIth) and facial (VIIth) nerve palsy. Echoencephalography is the first, safe, noninvasive, and cost-effective imaging modality available at bedside. No study on the use of echoencephalography in neonates for the diagnosis of MBS has been previously reported. METHODS: In this single tertiary center study, more than 18,000 neonates underwent echoencephalographic imaging over the span of two decades. Imaging was performed through the anterior, posterior, and lambdoid fontanelles. All neonates found to have calcifications of brainstem tegmental nuclei underwent additional imaging studies. Each neonate with MBS was carefully examined by the same investigator. RESULTS: Five neonates were shown to have punctate, bilateral, symmetrical tegmental pontine calcifications through all three acoustic windows. These calcifications extended caudally in most patients, and rostrally in 2 patients. Brainstem hypoplasia was best seen through the posterior fontanelle. Three out of five infants were noted to have brainstem hypoplasia with straightening of the floor of the fourth ventricle. In two children, facial collicular bulges and hypoglossal eminences were present. All five infants fulfilled clinical diagnostic criteria of MBS. In addition, a wide array of cerebral defects is identified. Echoencephalographic findings were confirmed by other imaging modalities. CONCLUSION: Knowledge of echoencephalographic features of MBS should improve its early recognition. A detailed description of the various imaging phenotypes of MBS is necessary to characterize the etiology of this heterogeneous congenital cranial dysinnervation disorder.

Ocular manifestations of two Filipinos with congenital fibrosis of the extraocular muscles

@#Congenital fibrosis of the extraocular muscles (CFEOM) is a rare, congenital, non-progressive disorder presenting with partial or total ophthalmoplegia, with variable degrees of ptosis in both eyes. We present the clinical manifestations of congenital fibrosis of the extraocular muscles in two patients. Both patients presented with bilateral ptosis and variable ophthalmoplegia with a chin-up posture. The ocular deviations have been noted since birth. No patient demonstrated a Marcus-Gunn jaw-winking phenomenon. Both patients had a mild refractive error with with-the-rule astigmatism. Deviation for both patients revealed exotropia with varying amounts of hypotropia and limitations in the movement of extraocular muscles. Both patients presented no abnormalities in the pupils. Neuroimaging revealed atrophy of the extraocular muscles. Diagnosis of CFEOM in a resource-poor setting is also challenging due to inaccessible gene testing. Manifestations of CFEOM vary across affected patients. CFEOM proposes challenges to the ophthalmologist with regards to management.

Crocodile tear syndrome treated with lacrimal gland incobotulinum toxin A injection: a report of two cases.

Crocodile tear syndrome (CTS) is a late complication of facial nerve palsy characterized by unilateral lacrimation in response to gustatory stimulation. We present 2 cases of patients diagnosed with CTS after recovering from unilateral idiopathic facial nerve palsy. Both patients underwent transconjunctival lacrimal gland incobotulinumtoxinA injection, with doses of 5-16 units. The patients were seen in clinic for post-treatment follow-up at 2 weeks, 3 months, and 6 months. Outcomes were measured by treatment efficacy and adverse drug effects. Following treatment, both patients reported resolution of gustatory lacrimation. The patient treated with 16 U experienced transient ptosis and diplopia following injection, whereas the patient treated with 5-7.5 U experienced no adverse effects.

Clinical and genetic characteristics of Chinese patients with congenital cranial dysinnervation disorders.

BACKGROUND: Congenital cranial dysinnervation disorders (CCDDs) are a group of diseases with high clinical and genetic heterogeneity. Clinical examinations combined with Magnetic resonance imaging (MRI) and whole exome sequencing (WES) were performed to reveal the phenotypic and genotypic characteristics in a cohort of Chinese CCDDs patients. RESULTS: A total of 122 CCDDs patients from 96 families were enrolled. All patients showed restrictive eye movements, and 46 patients from 46 families (47.9%, 46/96) were accompanied by multiple congenital malformations. Multi-positional high-resolution MRI was performed in 94 patients from 88 families, of which, all patients had hypoplasia of the cranial nerves except HGPPS patients and 15 patients from 15 families (17.0%,15/88) were accompanied by other craniocerebral malformations. WES was performed in 122 CCDDs patients. Ten pathogenic variants were detected in KIF21A, TUBB3, and CHN1 genes in 43 families. Three variants were unreported, including KIF21A (c.1064T > C, p.F355S), TUBB3 (c.232T > A, p.S78T) and CHN1 (c.650A > G, p.H217R). Of the 43 probands harboring pathogenic variants, 42 were diagnosed with Congenital Fibrosis of Extraocular Muscles (CFEOM) and one was Duane Retraction Syndrome (DRS). No definite pathogenic variants in known candidate genes of CCDDs were found in sporadic DRS, Möbius Syndrome (MBS) and Horizontal Gaze Palsy with Progressive Scoliosis (HGPPS) patients. The CFEOM patients harboring R380C, E410K and R262H variants in TUBB3 gene and F355S variant in KIF21A gene exhibited syndromic phenotypes. CONCLUSIONS: This study broadened the phenotypic and genotypic spectrums of CCDDs, and it was the largest clinical and genetic investigation for CCDDs patients from China. KIF21A and TUBB3 were the common pathogenic genes in Chinese CFEOM. MRI coupled with WES can provide a supportive diagnosis in patients with clinically suspected CCDDs.