Möbius-like syndrome associated with a 1;2 chromosome translocation

Exploring the Impact of Genetics in a Large Cohort of Moebius Patients by Trio Whole Exome Sequencing

Moebius syndrome (MBS) is a rare congenital disorder characterized by non-progressive facial palsy and ocular abduction paralysis. Most cases are sporadic, but also rare familial cases with autosomal dominant transmission and incomplete penetrance/variable expressivity have been described. The genetic etiology of MBS is still unclear: de novo pathogenic variants in REV3L and PLXND1 are reported in only a minority of cases, suggesting the involvement of additional causative genes. With the aim to uncover the molecular causative defect and identify a potential genetic basis of this condition, we performed trio-WES on a cohort of 37 MBS and MBS-like patients. No de novo variants emerged in REV3L and PLXND1. We then proceeded with a cohort analysis to identify possible common causative genes among all patients and a trio-based analysis using an in silico panel of candidate genes. However, identified variants emerging from both approaches were considered unlikely to be causative of MBS, mainly due to the lack of clinical overlap. In conclusion, despite this large cohort, WES failed to identify mutations possibly associated with MBS, further supporting the heterogeneity of this syndrome, and suggesting the need for integrated omics approaches to identify the molecular causes underlying MBS development.

Monozygotic twins discordant for a congenital cranial dysinnervation disorder with features of Moebius syndrome

Moebius syndrome is a congenital cranial dysinnervation disorder (CCDD) that presents with nonprogressive cranial nerve (CN) VI and VII palsies resulting in facial weakness and inability to abduct the eye(s). While many CCDDs have an underlying genetic cause, the etiology of Moebius syndrome remains unclear as most cases are sporadic. Here, we describe a pair of monochorionic, diamniotic twin girls; one with normal growth and development, and one with micrognathia, reduced facial expression, and poor feeding. Magnetic resonance imaging of the brain performed on the affected twin at 19 months of age showed severely hypoplastic or absent CN IV bilaterally, left CN VI smaller than right, and bilateral hypoplastic CN VII and IX, consistent with a diagnosis of a CCDD, most similar to that of Moebius syndrome. Genomic sequencing was performed on each twin and data was assessed for discordant variants, as well as variants in novel and CCDD-associated genes. No pathogenic, likely pathogenic, or variants of uncertain significance were identified in genes known to be associated with CCDDs or other congenital facial weakness conditions. This family provides further evidence in favor of a stochastic event as the etiology in Moebius syndrome, rather than a monogenic condition.

Unusual case of Trigeminal Neuralgia Associated with Poland -Moebius Syndrome

Moebius Syndrome is a rare congenital neurological condition characterized by paralysis of several cranial nerves, commonly the VI(Abducens) and VII(Facial) cranial nerves which causes lateral gaze strabismus and internal strabismus & classical mask like appearance respectively. Other cranial nerves such as V, VII, IX, X, XI, XII are rarely affected. Von Graefe and German neurologist Moebius (1888), after whom the syndrome was eventually named, provided the earliest descriptions of it. Although the etiopathogenesis is unknown, it appears to occur sporadically in the majority of cases, and some documented cases show hereditary predisposition. This paper presents a rare instance of trigeminal neuralgia associated with Moebius syndrome. According to the author's research, this is the first case of Poland Moebius syndrome with trigeminal neuralgia documented from India.

Directed yeast genome evolution by controlled introduction of trans-chromosomic structural variations

Naturally occurring structural variations (SVs) are a considerable source of genomic variation that can reshape the 3D architecture of chromosomes. Controllable methods aimed at introducing the complex SVs and their related molecular mechanisms have remained farfetched. In this study, an SV-prone yeast strain was developed using Synthetic Chromosome Rearrangement and Modification by LoxP-mediated Evolution (SCRaMbLE) technology with two synthetic chromosomes, namely synV and synX. The biosynthesis of astaxanthin is used as a readout and a proof of concept for the application of SVs in industries. Our findings showed that complex SVs, including a pericentric inversion and a trans-chromosome translocation between synV and synX, resulted in two neo-chromosomes and a 2.7-fold yield of astaxanthin. Also, genetic targets were mapped, which resulted in a higher astaxanthin yield, thus demonstrating the SVs' ability to reorganize genetic information along the chromosomes. The rational design of trans-chromosome translocation and pericentric inversion enabled precise induction of these phenomena. Collectively, this study provides an effective tool to not only accelerate the directed genome evolution but also to reveal the mechanistic insight of complex SVs for altering phenotypes.

Characterization of Hand Anomalies Associated With Möbius Syndrome

PURPOSE

To investigate the distinguishing morphological characteristics of the upper extremities in children with Möbius syndrome.

METHODS

Twenty-seven involved extremities in 14 patients with a diagnosis of Möbius syndrome were identified at 2 institutions. Medical records, radiographs, and clinical photographs were evaluated. Congenital hand differences were classified according to the Oberg, Manske, and Tonkin classification, and hands with symbrachydactyly were classified by the Blauth and Gekeler classification. The presence of other congenital anomalies was catalogued.

RESULTS

There was bilateral involvement in 93% of patients with congenital hand anomalies. Twelve patients demonstrated congenital hand anomalies and 2 patients had been diagnosed with arthrogryposis. Among the 12 patients with congenital hand anomalies, 21 hands were classifiable as symbrachydactyly by the Oberg, Manske, and Tonkin classification and could be categorized by the Blauth and Gekeler classification. Short finger type was the most common subtype of symbrachydactyly, present in 13 hands. Eleven of these 13 patients (85%) were primarily affected on the radial side of the hand. Proximal arm involvement was identified in 2 patients with symbrachydactyly, both of whom had Poland syndrome and an absent pectoralis major.

CONCLUSIONS

Symbrachydactyly in Möbius syndrome differs from the typical presentation of symbrachydactyly. Characteristically, there is a bilateral presentation with a strong predilection for radially based brachydactyly. These described characteristics may help the hand surgeon appropriately assess patients, especially those with radial-sided symbrachydactyly.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic III.

Multigenic truncation of the semaphorin-plexin pathway by a germline chromothriptic rearrangement associated with Moebius syndrome

Moebius syndrome (MBS) is a congenital disorder caused by paralysis of the facial and abducens nerves. Although a number of candidate genes have been suspected, so far only mutations in PLXND1 and REV3L are confirmed to cause MBS. Here, we fine mapped the breakpoints of a complex chromosomal rearrangement (CCR) 46,XY,t(7;8;11;13) in a patient with MBS, which revealed 41 clustered breakpoints with typical hallmarks of chromothripsis. Among 12 truncated protein-coding genes, SEMA3A is known to bind to the MBS-associated PLXND1. Intriguingly, the CCR also truncated PIK3CG, which in silico interacts with REVL3 encoded by the other known MBS-gene REV3L, and with the SEMA3A/PLXND1 complex via FLT1. Additional studies of other complex rearrangements may reveal whether the multiple breakpoints in germline chromothripsis may predispose to complex multigenic disorders.

Möbius syndrome with cardiac rhabdomyomas

BACKGROUND

Möbius syndrome is a rare congenital condition which presents not merely with 6th and 7th nerve palsies, but involves gaze paresis associated with craniofacial, limb, and other abnormalities. Heterogeneity is well known in patients with Möbius syndrome and rather than being of familial inheritance based on rare cases, it is much more recognized as a sporadic syndrome. We report an infant with features of congenital Möbius syndrome associated with cardiac rhabdomyomas in the absence of tuberous sclerosis.

MATERIALS AND METHODS

Observational case report of an infant seen at a tertiary academic center with genetic testing, ophthalmic, neurological, and cardiac clinical examination and imaging.

RESULTS

A newborn baby boy at birth was seen with multiple congenital craniofacial malformations, and respiratory distress. He was noted to have micrognathia, retrognathia, wide nasal bridge, low set ears, high arched palate, nonreducing bilateral talipes equinovarus and bilateral large angle esotropia with -4 abduction deficit and facial palsy, findings suggestive of Möbius Syndrome. MRI of the brain was unremarkable except for syringomyelia in the cervical spine. Echocardiography showed two cardiac rhabdomyomas in the right ventricle and ulltrasound of the abdomen showed mild right hydroneprosis. Cytogenetics revealed segmental loss at 21q21.2. Testing for tuberous sclerosis was negative for deletion or duplications of genes TSC1 and TSC2.

CONCLUSION

This case highlights the rare co-occurrence of cardiac rhabdomyomas with Möbius syndrome and new segmental loss at 21q21.2 on genetic testing. Findings could indicate not a "suggestion of Möbius", but rather the syndrome itself in association with cardiac defects.

Mobius Syndrome: A 35-Year Single Institution Experience

BACKGROUND

Mobius syndrome is a rare syndrome that is known to be associated with a variety of orthopaedic conditions including scoliosis, clubfoot, transverse limb deficiencies, Poland syndrome, and a myriad of hand conditions. To date, no large series exist to characterize the orthopaedic manifestations of Mobius syndrome.

METHODS

Medical records at a single tertiary pediatric institution were reviewed for all patients diagnosed with Mobius syndrome from January 1, 1980 to December 31, 2015. Records and radiographs were reviewed for associated orthopaedic conditions and their management.

RESULTS

In total, 44 patients with Mobius syndrome were identified. Age at presentation ranged from 6 days to 14 years. When compared with the general population, patients with Mobius syndrome had an increased incidence of clubfoot (41%), Poland syndrome (20%), and scoliosis (14%). Clubfoot treated both before and after the institution of Ponseti casting had a high rate of requiring posteromedial release, with a significant rate of subsequent revision. Hip dysplasia was noted in 1 patient and required surgical correction. Other associated syndromes included arthrogryposis, Pierre Robin syndrome, and chromosome 10 defect.

CONCLUSIONS

Mobius syndrome is accompanied by an increased rate of several orthopaedic problems; most notably clubfoot, scoliosis, and upper extremity differences that often require surgical treatment. The management of clubfoot in the setting of Mobius syndrome often requires surgical intervention due to failure of casting, and seems to have a higher rate of need for revision. Early involvement of orthopaedists in the care of patients with Mobius syndrome is often necessary. Orthopaedist should counsel families that treatment may be more complex than that of idiopathic disease.

LEVEL OF EVIDENCE

Level IV-case series.

An exome sequencing study of Moebius syndrome including atypical cases reveals an individual with CFEOM3A and a TUBB3 mutation

Moebius syndrome is characterized by congenital unilateral or bilateral facial and abducens nerve palsies (sixth and seventh cranial nerves) causing facial weakness, feeding difficulties, and restricted ocular movements. Abnormalities of the chest wall such as Poland anomaly and variable limb defects are frequently associated with this syndrome. Most cases are isolated; however, rare families with autosomal dominant transmission with incomplete penetrance and variable expressivity have been described. The genetic basis of this condition remains unknown. In a cohort study of nine individuals suspected to have Moebius syndrome (six typical, three atypical), we performed whole-exome sequencing to try to identify a commonly mutated gene. Although no such gene was identified and we did not find mutations in PLXND1 and REV3L, we found a de novo heterozygous mutation, p.E410K, in the gene encoding tubulin beta 3 class III (TUBB3), in an individual with atypical Moebius syndrome. This individual was diagnosed with near-complete ophthalmoplegia, agenesis of the corpus callosum, and absence of the septum pellucidum. No substantial limb abnormalities were noted. Mutations in TUBB3 have been associated with complex cortical dysplasia and other brain malformations and congenital fibrosis of extraocular muscles type 3A (CFEOM3A). Our report highlights the overlap of genetic etiology and clinical differences between CFEOM and Moebius syndrome and describes our approach to identifying candidate genes for typical and atypical Moebius syndrome.

Orthopedic Manifestations of Mobius Syndrome: Case Series and Survey Study

Background. Mobius Syndrome is a rare disease defined by bilateral congenital 7th nerve palsy. We focus on reporting the prevalence of orthopedic disease in this population. Methods. Twenty-three individuals with Mobius Syndrome underwent orthopedic physical examination, and additional 96 patients filled out a survey for self-reported orthopedic diagnoses. Results. Clubfoot was present in 60% of individuals in the physical exam series and 42% of those in the survey. Scoliosis was present in 26% and 28%, respectively. Poland's Syndrome was present in 17% and 30%. In addition to these findings, 27% of patients reported having difficulty with anesthesia, including difficulty in intubation and airway problems. Conclusion. An increased prevalence of scoliosis, clubfoot, transverse limb deficiencies, and Poland's Syndrome is identified in the setting of Mobius Syndrome. In the setting of several deformities often requiring surgical correction, a high incidence of anesthetic difficulty is noted and should be discussed with patients and other providers during surgical planning.

Examining the genetics of congenital facial paralysis--a closer look at Moebius syndrome

OBJECTIVES

The molecular underpinnings of Moebius syndrome (MBS) are diverse. This article provides a comprehensive summation of the genetic and etiologic literature underlying this disorder. Elucidating the genetic causes of the disorder can aid in earlier detection and treatment planning.

DESIGN

Articles from 1880-2013 were selected and reviewed by six researchers to understand all of the molecular theories and chronicity of advancements in the literature.

RESULTS

Mutations in the MBS1, MBS2, and MBS3 gene loci all have contributed to the development of MBS through various pathways. HOX family genes coding for homeobox domains, also, have been implicated in the abnormal development of the human brain. These are among the numerous genes that have been linked to the development of MBS.

CONCLUSION

Our study codified nascent findings of the molecular determinants of MBS. These findings add to a growing database of MBS-associated mutations and can be used to diagnose MBS and clarify pathogenesis.

[A case of Möbius syndrome with congenital facial palsy and supranuclear oculomotor palsy]

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.

[Eye and systemic manifestations of Mobius syndrome]

INTRODUCTION

Mobius syndrome is characterized by damage in the nucleus of the sixth and seventh cranial nerves, with subsequent facial palsy and abduction limitation of the eyes. The aim of this article is to describe the ophthalmological findings of the Mobius syndrome in Mexican children.

PATIENTS AND METHODS

A cross-sectional, retrospective, observational and descriptive study was conducted. A review was made of the clinical charts of patients with Mobius syndrome who were seen in the National Institute of Pediatrics in Mexico, between the years 2000 and 2010.

RESULTS

A total of 64 charts were reviewed. The most important findings were eye abduction limitation (100%), facial palsy (100%), esotropia (54%), epicanthus (51.5%), entropion (22%), and history of use of abortion inducers in the mother in the first trimester of pregnancy (28%). We also found exotropia and hypertropia in some cases.

CONCLUSIONS

Mobius syndrome has a wide spectrum of ophthalmological manifestations that are important to detect early in order to improve function and esthetics.

Hypogonadism and neurological diseases

Affected patients with hypogonadism have unnaturally low amounts of sex hormones that produce male and female sex characteristics. Males who suffer from this condition lack testosterone, while females fail to produce enough estrogen. Hypogonadism may be present at birth, or it may take effect years later following injury or illness to the sex glands. Hypogonadism has remarkable associations with variable medical disorders; however, it is characterized by a distinctive association with variable neurological disorders: such as epilepsy, ataxia, dysmyelination, nerve muscle disease, movement disorders, mental retardation and deafness. The remarkable neurological diseases with hypogonadism should not basically be regarded as coincidental findings, but possibly related to an intrinsic pathophysiological association.

[Etiology and genetic aspects of Möbius sequence]

Möbius sequence is a rare congenital disorder defined by partial or complete agenesis of the 6th and 7th cranial nerves, which control eye movement and facial expression. The etiology is unclear but genetic and teratogenic factors are thought to be involved. Ischemia affecting the cranial nerve nuclei is a possible pathomechanism of Möbius sequence. Most cases of Möbius sequence are sporadic but some familial cases are also known. The inheritance patterns of Möbius sequence are heterogeneous and can be autosomal recessive, autosomal dominant or even X-linked. Some candidate regions and candidate genes have been described but no causative gene has yet been confirmed.

Thalidomide and misoprostol: Ophthalmologic manifestations and associations both expected and unexpected

Thalidomide is a very potent teratogen capable of causing severe systemic malformations if the fetus is exposed during the sensitive period. Although structural anomalies of the eye can occur from thalidomide exposure, the most frequent eye complication is secondary to damage to the cranial nuclei in the brain stem, resulting in aberrant neurologic connections causing a condition of abnormal ocular movement, Duane syndrome. A less frequent anomalous neurologic complication is tearing when eating (paradoxical gustolacrimal tearing or "crocodile tears") or lack of emotional tearing. The involvement of the 6th and 7th cranial nerves, often seen together in the thalidomide-affected individual, is also characteristic of Möbius syndrome/sequence. This syndrome usually occurs sporadically, but characteristic findings of this condition have also been observed in South American children who were born after an unsuccessful attempt to induce abortion with the prostaglandin drug misoprostol (Cytotec). Aberrant tearing also occurs in some individuals with Möbius syndrome. Autism spectrum disorder (ASD), an unexpected associated finding in a Swedish thalidomide study, is now also noted in Möbius studies, in patients both with and without exposure to misoprostol.

Möbius syndrome as a syndrome of rhombencephalic maldevelopment: a case report

Möbius syndrome is a rare congenital disorder characterized by congenital facial weakness with impairment of ocular abduction. It is considered as a rhombencephalic disorder, and is often accompanied with hypoplasia of the pons and cerebellum. Here we report a male infant who had congenital facial asymmetry with absence of right-sided expression. Evident developmental delay was also found. The bilateral auditory brain stem response showed no response at 85dB. A reconstructive brain magnetic resonance imaging (MRI) revealed the absence of the right facial nerve as well as hypoplasia of the pons and cerebellum of the same side. Some voluntary contraction over the patient's right lower face was noted after facial muscle electrical stimulation.

Möbius Syndrome: A Case with Oral Involvement

Möbius syndrome is a rare congenital condition that is characterized clinically by paralysis of a group of cranial nerves. It presents diverse manifestations that can have negative repercussions on the quality of life of affected individuals. This article presents a clinical case of a child with the syndrome and addressed the clinical manifestations and difficulties experienced during dental treatment. Knowledge of the etiopathological aspects and clinical manifestations of the condition is essential to perfecting treatments that aim to improve the quality of life of such individuals and their families.

Refinement of the locus for hereditary congenital facial palsy on chromosome 3q21 in two unrelated families and screening of positional candidate genes

Hereditary congenital facial palsy (HCFP) is an autosomal-dominant disorder consisting of paresis or paralysis of the VIIth (facial) cranial nerve. Genetic heterogeneity for this disorder has been suggested based on linkage analysis in two large Dutch families. Two loci have been identified, one on chromosome 3q21.2-q22.1 (HCFP1) and another on chromosome 10q21.3-q22.1 (HCFP2). Here, we report linkage analysis in a large Pakistani family with dominant congenital facial palsy. A region cosegregating with the disorder was identified on the long arm of chromosome 3, which overlaps with the previously identified HCFP1 locus on chromosome 3q21-q22, thus confirming the involvement of this locus in HCFP. The critical region could be reduced from 5.7 to 3.0 cM between the markers D3S3607 and GDB ID:11524500. In addition, mutation analysis on seven candidate genes: KLF15, FLJ40083, PODXL2, TMCC1, PLEXIN-A1, PLEXIN-D1, and GATA-2, was performed. All genes are located within the critical interval of the Dutch HCFP1 family. The genes PODXL2, PLEXIN-D1, GATA-2, and TMCC1 are also located within the smaller critical interval of the Pakistani HCFP family. Based on the results obtained, all seven genes could be excluded as causative genes in HCFP.

A report of paracentric inversion of chromosome 8 in Moebius syndrome

An eight-year-old girl with bilateral facial paresis and restricted eye movements was diagnosed with Moebius syndrome. A chromosomal analysis showed a paracentric inversion on the long arm of chromosome 8 (46, XX, inv(8) (q21.3q24.13)). Candidate genes have been found on chromosomes 3q21, 10q21, and 13q12. We discuss the genes which are known to have associated ocular movement dysfunction in the 8q21-24 region. We hope this case will add to the current body of knowledge regarding Moebius syndrome and its genetics.

The genetics of strabismus

Strabismus (misalignment of the eyes; also known as "squint") comprises a common heterogeneous group of disorders characterised by a constant or intermittent ocular deviation often associated with amblyopia (uniocular failure of normal visual development) and reduced or absent binocular vision. The associated poor cosmetic appearance may also interfere with social and psychological development. Extensive twin and family studies suggest a significant genetic component to the aetiology of strabismus. The complexity of the molecular basis of strabismus is now beginning to be elucidated with the identification of genetic loci and disease causing genes. Currently greater insights have been gained into the incomitant subtype (differing magnitude of ocular misalignment according to direction of gaze), whereas less is known about the pathogenesis of the more common childhood concomitant strabismus. It is hoped that a greater understanding of the molecular genetics of these disorders will lead to improved knowledge of disease mechanisms and ultimately to more effective treatment. The aim of this paper is to review current knowledge of the molecular genetics of both incomitant and concomitant strabismus.

Autism associated with conditions characterized by developmental errors in early embryogenesis: a mini review

Autism is a complex developmental disorder without an established single etiology but with significant contributions from genetic studies, functional research, and neuropsychiatric and neuroradiologic investigations. The purpose of this paper is to review the findings in five studies involving individuals manifesting the characteristic findings of autism spectrum disorder associated with malformations and dysfunctions known to result from early embryogenic defects. These investigations include two associated with teratogens (thalidomide embryopathy, Mobius sequence with misoprostol) and three (most Mobius sequence cases, CHARGE association, Goldenhar syndrome) with no known etiology. These studies suggest that early embryonic development errors often involving cranial nerve palsies, internal and external ear malformations, ophthalmologic anomalies, and a variety of systemic malformations may be associated with autism spectrum disorders statistically more frequently than expected in a normal population. Although the exact time of developmental insult for each condition cannot be identified, the evidence is that it may occur as early as week 4 to 6+ of embryogenesis.

Sequence analysis of the PLEXIN-D1 gene in Möbius syndrome patients

Möbius syndrome is a rare congenital disease characterized by the paralysis of the facial nerve, accompanied by impaired ocular abduction. We have performed an extensive mutation analysis on a recently identified positional candidate gene, PLEXIN-D1, for Möbius syndrome 2 mapping to chromosome 3q21-q22. Southern analysis of patients from the Möbius syndrome 2 family and 41 isolated Möbius syndrome patients did not reveal chromosomal abnormalities in the PLEXIN-D1 gene. Direct sequencing of deoxyribonucleic acid from familial patients, and single-strand conformational polymorphism analysis of PLEXIN-D1 in 41 isolated patients identified 18 nucleotide changes. Seventeen of these 18 changes could be dismissed as polymorphisms, as they did not co-segregate with the disease, or were present in a control group. A single nucleotide change identified in intron 29 of an isolated Möbius syndrome patient could not be identified in a control group. However, the position of this nucleotide change makes it highly unlikely that it could be causative for Möbius syndrome in this patient because it does not affect known splicing sequences. Likewise, reverse transcriptase polymerase chain reaction analysis in patients from the Möbius syndrome 2 family did not reveal splicing aberrations, and revealed bi-allelic expression, ruling out the possibility of promoter disrupting mutations. Taken together, these results lead to the exclusion of the PLEXIN-D1 gene as the causative gene in Möbius syndrome 2, and in isolated Möbius syndrome.

Watershed infarcts in the fetal and neonatal brainstem. An aetiology of central hypoventilation, dysphagia, Möibius syndrome and micrognathia

Watershed zone infarcts of the human cerebral cortex at the overlapping junctions of the anterior and middle cerebral arterial territories are well known. Another watershed zone exists in the brainstem tegmentum, between the terminal perfusion zones of the paramedian penetrating and long circumferential arteries, which are paired segmental vessels arising from the basilar artery. The vertebrobasilar circulation achieves its mature configuration and caudorostral flow by 9 weeks gestation. Systemic hypotension and other conditions of reduced basilar perfusion in the fetus, either early or late in gestation, may result in symmetrical longitudinal columns of infarction in the midbrain and tegmentum of the pons and medulla oblongata and laminar necrosis of the midbrain tectum. Within this zone are cranial nerve nuclei III-XII, the nucleus and tractus solitarius or central pneumotaxic center, as well as the nucleus ambiguus and other somatic motor nuclei that subserve muscles of swallowing, mastication and tongue movement. Watershed infarcts in the human fetal and neonatal brainstem are clinically expressed as multiple cranial neuropathies, failure of central respiratory drive and apnea, dysphagia and aspiration, Möbius syndrome and Pierre Robin sequence. MRI is sometimes helpful, but most of the involved neuroanatomical structures are beneath the resolution of present imaging techniques, and the diagnosis during life depends upon clinical neurological examination of the neonate, sometimes supported by evoked potential studies. Postmortem examination confirms the diagnosis and dates the lesions, but also contributes to better understand transient or persistent vascular insufficiencies in the fetal and neonatal brainstem.

Twenty-year behavioral follow-up of a 1;13 chromosomal translocation and Mobius syndrome presenting with poor impulse control, exhibitionism, and aggression

Mobius syndrome is a rare disorder characterized by agenesis or aplasia of the facial or abducens nerve motor nuclei and other features including central nervous system and behavioral abnormalities. We report an adult case of Mobius syndrome variant presenting with poor impulse control, aggression, and exhibitionism. Karyotyping revealed a 46 XY, t(1;13)(p34.3;q12.3) translocation. The subject had been presented 20 years previously as the index case of a three-generation pedigree.

A case of Moebius syndrome in association with Klinefelter syndrome

PURPOSE

To describe an infant affected by Klinefelter syndrome, who also demonstrated clinical signs of Moebius syndrome.

METHODS

A clinical case report.

RESULTS

A male infant was born full-term to a healthy couple after an unremarkable pregnancy. Several dysmorphic features and generalized hypotonia were noted at birth. Chromosome study revealed a 47, XXY chromosome pattern, which is consistent with Klinefelter syndrome. The patient also demonstrated clinical findings of Moebius syndrome: bilateral horizontal gaze palsy, bilateral cranial nerve seven palsy, pointed tongue, pectoral muscle hypoplasia, and clubfeet.

CONCLUSION

We report the first clinical case of a patient with Klinefelter syndrome who was also affected by Moebius syndrome. Although clinically intriguing, coexistence of the two syndromes most likely represents a chance occurrence.

Development of speech, feeding, eating, and facial expression in Möbius sequence

OBJECTIVE

Möbius sequence is a rare congenital disorder with the primary diagnostic criteria of congenital facial and abducens nerve palsy. Involvement from other cranial nerves is common. Orofacial anomalies and limb malformations may be associated with the disorder. Mental retardation and autism have been reported in some. The aim of this study was to describe orofacial dysfunction observed in a prospective, multidisciplinary study of individuals with Möbius sequence.

METHODS

Twenty-five patients with Möbius sequence, aged 2 months to 54 years, participated in the study. Clinical observations by different medical specialists were collected in an established database. Dentists and a speech pathologist made the orofacial examination. The parents or the patient described orofacial function and dysfunction through interviews and a questionnaire.

RESULTS

Bilateral facial palsy was observed in 16 patients, unilateral palsy in 9. Observed orofacial anomalies were tongue dysfunction (16), micrognatia (8), microglossia (7), cleft palate (4), and cleft lip (1). Seventeen had speech problems, 16 reported feeding difficulties in infancy, 14 eating problems, and 8 drooling.

CONCLUSIONS

Orofacial problems are common in Möbius sequence and have a significant impact on the quality of life for the patient and for the whole family. Early intervention by a speech pathologist and a paediatric dentist should be undertaken to improve orofacial function and symptoms. Plastic surgery, oral motor training, facial massage, speech therapy, and orthodontic treatment are some of the therapy methods that can be considered.

Structural chromosomal anomaly in mental retardation

This article reports the structural chromosomal anomaly in three patients with mental retardation: (i) Proband was a five year old girl with reciprocal retardation (1; 2) (p32; q11) (ii) Proband, female of 14 years. Her karyotype showed translocation (1; 3) (q42; q13). The translocations were de novo in origin (iii) Proband showed variant 13 as the giant satellite over its short arm, and this was paternal in origin. Proband, eighteen months old male child had microcephaly and seizures. These two features may be because of autosomal recessive condition. This report emphasises the need for kayotyping to provide a clear cut diagnosis and appropriate counselling.

A second gene for autosomal dominant Möbius syndrome is localized to chromosome 10q, in a Dutch family

Möbius syndrome (MIM 157900) consists of a congenital paresis or paralysis of the VIIth (facial) cranial nerve, frequently accompanied by dysfunction of other cranial nerves. The abducens nerve is typically affected, and often, also, the hypoglossal nerve. In addition, orofacial and limb malformations, defects of the musculoskeletal system, and mental retardation are seen in patients with Möbius syndrome. Most cases are sporadic, but familial recurrence can occur. Different modes of inheritance are suggested by different pedigrees. Genetic heterogeneity of Möbius syndrome has been suggested by cytogenetic studies and linkage analysis. Previously, we identified a locus on chromosome 3q21-22, in a large Dutch family with Möbius syndrome consisting essentially of autosomal dominant asymmetric bilateral facial paresis. Here we report linkage analysis in a second large Dutch family with autosomal dominant inherited facial paresis. After exclusion of >90% of the genome, we identified the locus on the long arm of chromosome 10 in this family, demonstrating genetic heterogeneity of this condition. The reduced penetrance suggests that at least some of the sporadic cases might be familial.

The möbius sequence: a relook

BACKGROUND

The constellations of findings often referred to as Mobius syndrome might be better described as Mobius sequence, because the term sequence defines a cascade of secondary events after an embryonic insult from heterogeneous causes. Classic clinical findings include evidence of sixth and seventh cranial nerve involvement, often with associated malformations of limbs, craniofacial structures, and other cranial nerves.

METHODS

A prospective study was undertaken in Sweden of 25 patients who showed characteristic findings of Mobius sequence.

RESULTS

Of the patients who did not have strabismus surgery, 10 patients had straight eyes in the primary position, 7 had esotropia, 2 had exotropia, and 1 had hypertropia. All had significant limitation of abduction, except 1 patient with exotropia who showed minimal underaction on abduction but a large limitation of adduction. In the description in these early cases, some patients manifested a clinical pattern resembling a horizontal gaze paresis. Narrowing of the palpebral fissure on adduction similar to that seen in Duane syndrome was observed in a few cases. Two patients had ptosis. Nineteen patients had diminished facial expression bilaterally, often asymmetric, and 6 cases appeared to be unilateral. Seven patients had abnormal tearing. Associated systemic findings included Poland anomaly (2), club feet or other limb anomalies (8), micrognathia (8), tongue malformations (17), cleft palate (5), and speech problems (18). An unusual finding was autism syndrome (6) or autism-like syndrome (1).

CONCLUSIONS

The associated findings in Mobius sequence may give further clues to the location and timing of the developmental disturbance. The wide range of ocular motility patterns suggests that the previous concept of a lesion solely in the sixth nerve nucleus is an inadequate explanation for these findings.

The facial nerve. Current trends in diagnosis, treatment, and rehabilitation

Facial paralysis is a potentially devastating disorder with numerous implications. Multiple entities must be considered in its etiology, and recent advances in microbiology, radiographic imaging, electrodiagnostic testing, and microsurgery have provided great insight into the pathophysiology, diagnosis, treatment, and rehabilitation of the facial nerve. Recent DNA PCR testing has shed new insight into the potential cause for Bell's palsy. This article focuses on the evaluation, differential diagnosis, medical treatment, and rehabilitation of facial nerve pathology with primary emphasis on facial paralysis. Surgical management is also discussed, including reanimation of the paralyzed face.