Moebius sequence –a multidisciplinary clinical approach

Abstract

BackgroundMoebius Sequence (MS) is a rare disorder defined by bilateral congenital paralysis of the abducens and facial nerves in combination with various odontological, craniofacial, ophthalmological and orthopaedic conditions. The aetiology is still unknown; but both genetic (de novo mutations) and vascular events in utero are reported. The purpose of present study was through a multidisciplinary clinical approach to examine children diagnosed with Moebius-like symptoms. Ten children underwent odontological, ophthalmological, obstetric, paediatric, orthopaedic, genetic, radiological and photographical evaluation. Five patients maintained the diagnosis of MS according to the diagnostic criteria.ResultsAll five patients had bilateral facial and abducens paralysis confirmed by ophthalmological examination. Three of five had normal brain MR imaging. Two had missing facial nerves and one had missing abducens nerves. The Strengths and Difficulties Questionnaire (SDQ) showed normal scores in three of five patients. Interestingly, two of five children were born to mothers with uterine abnormalities (unicornuate/bicornuate uterus). In the odontological examination three of five showed enamel hypomineralisation. All five had abnormal orofacial motor function and maxillary prognathism. Two patients had adactyly, syndactyly and brachydactyly. None of the five patients had Poland anomaly, hip dislocation or dysplasia but all had a mild degree of scoliosis. We observed congenital club-feet, calcaneovalgus deformities, macrodactyly of one or more toes or curly toes. Pedobarography showed plantar pressures within normal ranges.ConclusionsAdherence to standard diagnostic criteria is central in the diagnosis of MS. An accurate diagnosis is the basis for correct discussion of other relevant concomitant symptoms of MS, genetic testing and evaluation of prognosis. The multidisciplinary approach and adherence to diagnostic criteria taken in present study increases the knowledge on the relationship between genotype, phenotype and symptomatology of MS.

Congenital facial palsy and emotion processing: The case of Moebius syndrome

“…44,45 Most patients present normal intelligence, while rare cases of autistic-like behaviors (0%-5%) and mild mental retardation (9%-15%) have been reported. 44,46,47 The syndrome is also referred to as Moebius "sequence," term which defines a cascade of secondary events after an initial insult during the embryonic development, 13,48 as well as a possible genetic etiology 49 (see Box 1).…”

Orofacial motor dysfunction in Moebius syndrome

“…Normal MMOC values have been reported in a 7-year-old child and three older patients (15-19y). 18 Because mastication efficiency results from muscle growth and coordination of the lips, jaws, and cheeks, children with MBS typically show abnormal chewing function. 5 Dysfunction was manifest for a quarter of our population who still needed alterations to food texture at 5 years of age.…”

Neuroimaging Findings in Moebius Sequence

“…5 The term "sequence" is preferred to "syndrome" because it defines a cascade of secondary events after an initial insult during the embryonic period. 6 In histopathologic studies of patients affected by Moebius sequence, the main abnormality is found in the pontine tegmentum where the nuclei for cranial nerve VI are located and the intra-axial fibers of the seventh cranial nerve are crossing posterior to these nuclei (the facial colliculus). 14 Brain stem ischemia during embryogenesis is the most accepted cause of Moebius sequence.…”

“…These result in a defect in facial branchiomotor neuron migration, supporting these genes as causative for at least a portion of Moebius sequence cases. 6 Clinically, patients have unilateral or bilateral congenital facial paralysis and esotropia with preservation of the vertical gaze. Known brain MR imaging findings in Moebius sequence are based on small case series.…”

“…5 Both genetic and nongenetic factors are believed to be important for the development of Moebius sequence. 6 Currently, the most accepted etiology of this syndrome is hypoxic-ischemic injury to the brain stem during development, which is supported by histo-pathologic evaluation of postmortem Moebius sequence brains with evidence of focal necrosis with areas of gliosis and calcification in vascular territories of the brain stem. 7 Moebius sequence diagnosis is based on clinical criteria after exclusion of similar syndromes such as congenital fibrosis of the extraocular muscles in which there is severe congenital strabismus, ptosis, and vertical gaze palsy.…”