Characterization of ocular motor deficits in congenital facial weakness: Moebius and related syndromes

Brain (Impact Factor: 9.2). 02/2014; 137(4). DOI: 10.1093/brain/awu021
Source: PubMed


Congenital facial weakness is present in a heterogeneous group of conditions. Among them is Moebius syndrome, which has been defined as a disorder with congenital, non-progressive facial weakness and limited abduction of one or both eyes. It is typically attributed to agenesis of the abducens and facial cranial nerves. This paper details ocular motor findings of 40 subjects (23 months to 64 years; 24 females, 16 males) with congenital facial weakness: 38 presented at a Moebius Syndrome Conference and two were clinic patients. A new classification scheme of patterns based on ocular motor phenotype is presented. Of 40 subjects, 37 had bilateral and three had unilateral facial weakness. The most common ocular motor pattern (Pattern 1, n = 17, 43%) was bilateral horizontal gaze palsy with intact vertical range. Pattern 2 (n = 10, 26%) was bilateral horizontal gaze palsy with variable vertical limitations. Pattern 3, which was rare, was isolated abduction deficits (n = 2, 5%). Others had full motility range and did not meet minimal criteria for the diagnosis of Moebius syndrome (Pattern 4, n = 10, 26%). One subject was too severely affected to characterize. Abnormal vertical smooth pursuit was present in 17 (57%) of 30 subjects: nine with Pattern 1, five with Pattern 2, and three with Pattern 4. Abnormal vertical saccades were present in 10 (34%) of 29 subjects. Vertical saccades appeared slow in nine: six with Pattern 1 and three with Pattern 2. Vertical saccades were absent in one subject with Pattern 2. Abnormal vertical optokinetic nystagmus was present in 19 (68%) of 28 subjects: 10 with Pattern 1, six with Pattern 2, one with Pattern 3, and two with Pattern 4. Reduced convergence was present in 19 (66%) of 29 subjects: nine with Pattern 1, six with Pattern 2, one with Pattern 3, and three with Pattern 4. The most common pattern of ocular motor deficit in Moebius syndrome is bilateral horizontal gaze palsy from pontine abducens nuclear defects, rather than abducens nerve involvement. Defects in the range or dynamic properties of vertical movements in subjects with congenital facial weakness may suggest involvement of ocular motor structures in the midbrain, including oculomotor nerves or nuclei, vertical supranuclear saccadic centres, and convergence neurons. Such deficits were found even in subjects with full vertical motility range. Classification of patterns of ocular motor deficits in congenital facial weakness may assist with further delineation of anatomic localization and identification of genetic deficits underlying these disorders.

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    ABSTRACT: Background Moebius syndrome is a rare disorder with minimum clinical criteria of congenital facial weakness in association with impairment in abduction of one or both eyes. Mirror movements are not known to be associated with Moebius syndrome. Case Report We present three patients who meet minimum criteria for a diagnosis of Moebius syndrome and who also display mirror movements. Discussion This case series suggests that Moebius syndrome may be associated with mirror movements. Further investigation to delineate the genetic etiologies of Moebius syndrome is ongoing. Patients with Moebius syndrome and mirror movements may represent a specific subclass of this disorder.
    07/2014; 4:256. DOI:10.7916/D83F4MR8
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    ABSTRACT: An 18-year-old man with congenital weakness in the facial and mastication muscles was referred to us. His facial senses were intact; however, the bilateral massetter and facial muscles were extremely weak and atrophic. He presented lagophthalmos and had difficulty in closing his mouth. The voluntary movements of his left eye, such as abduction, adduction, and elevation, were partially impaired, without the impairment of the Bell phenomenon. Nerve conduction studies of the facial nerves revealed normal distal latencies for bilateral orbicularis oculi. Blink reflexes were not evoked on both sides. Needle electromyography showed a chronic neurogenic change in the tongue. A biopsy of the biceps brachii and skin did not show abnormality. We diagnosed his condition as Möbius syndrome with congenital facial palsy and supranuclear oculomotor palsy. Möbius syndrome, which manifests itself as congenital and non-progressing facial and abducens palsy, is associated with many clinical symptoms and is probably heterogenous nosological entity. Although several cases of Möbius syndrome with supranuclear binocular elevation palsy were previously known, this is the first case of Möbius syndrome presenting supranuclear monocular elevation palsy.
    04/2015; 55(4):233-7. DOI:10.5692/clinicalneurol.55.233
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    ABSTRACT: Möbius syndrome (MBS) is a neurological disorder that is characterized by paralysis of the facial nerves and variable other congenital anomalies. The aetiology of this syndrome has been enigmatic since the initial descriptions by von Graefe in 1880 and by Möbius in 1888, and it has been debated for decades whether MBS has a genetic or a non-genetic aetiology. Here, we report de novo mutations affecting two genes, PLXND1 and REV3L in MBS patients. PLXND1 and REV3L represent totally unrelated pathways involved in hindbrain development: neural migration and DNA translesion synthesis, essential for the replication of endogenously damaged DNA, respectively. Interestingly, analysis of Plxnd1 and Rev3l mutant mice shows that disruption of these separate pathways converge at the facial branchiomotor nucleus, affecting either motoneuron migration or proliferation. The finding that PLXND1 and REV3L mutations are responsible for a proportion of MBS patients suggests that de novo mutations in other genes might account for other MBS patients.
    Nature Communications 06/2015; 6. DOI:10.1038/ncomms8199 · 11.47 Impact Factor

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