Heterogeneity and pleiotropism in the Moebius syndrome

Three families affected by Moebius syndrome are described. The difference in patterns of inheritance and the variability in phenotype encountered in these families suggest that there is considerable heterogeneity and pleiotropism in this disorder.     

Moebius syndrome in a child and extremity defect in her father

A child with Moebius syndrome and minor extremity anomalies is described. Her father had a transverse defect of the right arm with absence of the radius and ulna just below the elbow but no cranial nerve dysfunction. While possibly unrelated, review of the literature suggests these anomalies may both be part of a single broad spectrum syndrome, perhaps dominantly inherited.     

Abnormal B.A.E.P. in a family with Moebius syndrome: evidence for supranuclear lesion

A family with Moebius syndrome is presented. Neurological lesions in the affected members are various: complete VI and VII cranial nerves palsy associated with mental retardation in the proband; left convergent strabismus and mental retardation in a brother of the proband and only mental retardation in a sister of the proband. The brainstem auditory evoked potentials (B. A.E.P.), investigated in the proband and his affected sister, are abnormal. The presence of the anomaly after the 3rd wave is consistent with a disfunction of the auditory tract at a supranuclear level. The mental deficiency and the supranuclear site of the acoustic lesion are an indication for a more general involvement of C.N.S. than cranial nerve nuclei alone.
Karyotype and dermatoglyphics of the three affected subjects were normal. The authors hypothesized the same disorganogenetic factor acting very early (4th-6th week of gestational age) on the metamerization process of limb buds mesoderm and brainstem gray matter.     

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.     

A severe case of Moebius syndrome with calcification on the fourth ventricular floor

We report the case of a Japanese girl with a severe type of Moebius syndrome. Her morphological features were a mask-like face, limitation of horizontal eye movements, severe bulbar palsy, multiple and bilateral arthrogryposis including the elbow, knee, and ankle joints, and clubfeet. After birth, her general condition became worse because of repeated apneic spells and aspiration pneumonias due to dysphagia. She finally required tracheotomy. Computed tomography (CT) of the brain revealed minute calcifications on the fourth ventricle floor; this may have been due to severe damage to the brain stem. It is most likely that the various manifestations in our patient were due to disturbance of the blood supply to arteries perfusing the brain stem and to some other arteries, at a critical stage of fetal development. Received: November 15, 1996 / Accepted: October 3, 1997     

Genetic factors in human sleep disorders with special reference to Norrie disease, Prader–Willi syndrome and Moebius syndrome

Sleep–wake problems are common in specific inborn errors of metabolism and structure of the central nervous system. Psychological factors, behavioural difficulties, metabolic disturbances, and widespread rather than focal damage to the nervous system are present in many of these diseases and all influence the sleep–wake cycle. However, a number of conditions cause relatively focal damage to the neuroanatomical substrate of sleeping and waking. These include fatal familial insomnia, with involvement of the prion protein gene on chromosome 20, Norrie disease, the Prader–Willi syndrome and the Moebius syndrome. The last three important conditions, although rare, are considered in detail in this review. They result in sensory deprivation, hypothalamic and mid-brain damage, and involve the X-chromosome, chromosome 15, and chromosome 13, respectively. These conditions cause a wide variety of sleep disturbance, including parasomnias, daytime sleepiness, and a condition like cataplexy. The place of the relevant gene products in normal sleep regulation needs further exploration.     

Frequency of narcolepsy symptoms and other sleep disorders in narcoleptic patients and their first-degree relatives

Narcolepsy is a rare neurological sleep disorder affecting around 0.05% of the general population. Genetic factors are known to have an important role in narcolepsy. However, because of its very low prevalence, it is difficult to have groups of comparison between first-degree relatives and general population subjects in order to identify a specific spectrum of disorders in these families. Consequently, from 157 Italian patients with narcolepsy, 263 first-degree relatives were recruited, two refused to participate. These family members were compared with a matched group of 1071 subjects selected from a sample of 3970 subjects representative of the general population of Italy (46 million inhabitants). Finally, 68 spouses of narcoleptic patients were used to assess for possible role of environmental factors. All subjects were interviewed by telephone using the Sleep-EVAL system. Nineteen cases of narcolepsy were discovered among the first-degree relatives of 17 probands (10.8%). Compared with the general population subjects, the relative risk of narcolepsy among female first-degree relatives was of 54.4 and of 105.1 among male first-degree relatives. First-degree relatives were also at higher risk for idiopatic hypersomnia (OR: 23.0), obstructive sleep apnea syndrome (OR: 6.8), adjustment sleep disorder (OR: 4.0), insufficient sleep syndrome (OR: 7.0), circadian rhythm disorders (OR: 2.5), REM behavior disorder (OR: 4.4), and sleep talking (OR: 2.0). The vulnerability to sleep disorders is very high in first-degree relatives and the link with different expressivity and severity of hypersomnia can be confirmed.     

Molecular genetic screening of MBS1 locus on chromosome 13 for microdeletions and exclusion of FGF9, GSH1 and CDX2 as causative genes in patients with Moebius syndrome

Moebius syndrome is a rare disorder primarily characterized by congenital facial palsy, frequently accompanied by ocular abduction anomalies, and occasionally associated with orofacial, limb and musculoskeletal malformations. Abnormal development of cranial nerves V through XII underlines the disease pathogenesis. Although some investigations suggested that a causative gene may lie on 13q12.2–q13, there have been no molecular studies targeting possible microdeletions in this region to date. In the present study, we performed microdeletion analyses on 13q12.11–q13 in nine patients, and sequenced three candidate genes in nineteen patients for functional relevance and further resolution of our screening. We ruled out microdeletions on the critical region as a common cause of Moebius syndrome and excluded FGF9, GSH1 and CDX2 genes.     

The clinical spectrum of narcolepsy with cataplexy: a reappraisal

In the absence of a golden standard for the diagnosis of narcolepsy, the clinical spectrum of disorder remains controversial. The aims of this study were (1) to determine frequency and characteristics of sleep-wake symptoms in patients with narcolepsy with cataplexy, (2) to compare clinical characteristics with results of ancillary tests, and (3) to identify factors that discriminate narcolepsy from other conditions with excessive daytime sleepiness (EDS). We prospectively studied 57 narcoleptics with cataplexy, 56 patients with non-narcoleptic hypersomnia (H), and 40 normal controls (No). Based on suggested and published criteria, we differentiated between narcoleptics with definite cataplexy (N) and narcoleptics without definite cataplexy (possible cataplexy, NpC). Assessment consisted of questionnaires [all patients and controls, including the Ullanlinna Narcolepsy Score (UNS)], polysomnography (all patients), multiple sleep latency test (MSLT) and human leukocyte antigen typing (in most narcoleptics). A new narcolepsy score based on five questions was developed. Data were compared with those of 12 hypocretin-deficient narcoleptics (N-hd). There were significant differences between N and NpC (including mean sleep latency on MSLT), but none between N and N-hd. A score of sleep propensity during active situations (SPAS) and the frequency of sleep paralysis/hallucinations at sleep onset, dreams of flying, and history of sleep shouting discriminated N from H and No (P < 0.001). Cataplexy-like symptoms in H (18%) and No (8%) could be discriminated from 'true' cataplexy in N on the basis of topography of motor effects, triggering emotions and triggering situations (P < 0.001). Our narcolepsy score had a similar sensitivity (96% versus 98%) but a higher specificity (98% versus 56%) than the UNS. Analysis of co-occurring symptoms in narcolepsy revealed two symptom complexes: EDS, cataplexy, automatic behaviors; and sleep paralysis, hallucinations, parasomnias. Low/undetectable cerebrospinal fluid hypocretin-1 levels and a history of definite cataplexy identify similar subgroups of narcoleptics. Specific questions on severity of EDS (SPAS score) and characteristics of cataplexy allow the recognition of subgroups of narcoleptics and their differentiation from non-narcoleptic EDS patients, including those reporting cataplexy-like episodes. The existence of co-occurring symptoms supports the hypothesis of a distinct pathophysiology of single narcoleptic symptoms.     

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.     

Poland-Moebius syndrome in a boy and Poland syndrome in his mother

A 4 4/12-year-old boy with the Poland-Moebius syndrome, whose mother had the POland syndrome, is presented. This is the first report of the occurrence of both syndromes in the same family, suggesting that they are expressions of the same autosomal dominant gene.     

Schinzel-Giedion syndrome: Report of two sibs

We report on two further cases, a sister and a brother, with Schinzel-Giedion syndrome. Both presented the following manifestations: “coarse face” with midface retraction, agenesis of corpus callosum, bilateral hydronephrosis, and typical skeletal anomalies. Patient 1 had a malignant sacrococcygeal teratoma. This is the third case of malignancy in this syndrome. Patient 2 died shortly after birth. © 1995 Wiley-Liss, Inc.     

Postaxial acrofacial dysostosis: Report on two patients

We report on 2 patients with the postaxial acrofacial dysostosis (AFD) syndrome. One patient was an isolated case; the other had an equally affected brother previously described [Richieri-Costa and Guion-Almeida, 1989]. Recurrence in sibs suggests autosomal recessive inheritance. © Wiley-Liss, Inc.     

Ipsilateral foot and contralateral hand anomalies in a patient with Poland-Moebius syndrome

This report describes a patient who had bilateral facial nerve paralysis, external ophthalmoplegia, absence of pectoralis major muscle at right side, ipsilateral hand and foot, and contralateral hand anomalies. To our knowledge, this is the first patient with Poland syndrome reported in combination with Moebius syndrome, presenting with contralateral hand and ipsilateral foot anomalies.     

A new short rib syndrome: Report of two cases

We describe two unrelated malformed infants who died shortly after birth and who had multiple congenital anomalies including hydrops and ascites, facial abnormalities (with median cleft of the upper lip), narrow thorax, protuberant abdomen, and short, bowed limbs. Postmortem radiographs showed very short ribs and disproportionately short long tubular bones; no metaphyseal abnormalities were present. Comparison with earlier described short-rib/short-rib-polydactyly syndromes suggest that the disorder present in our two cases is a new type of short-rib syndrome. One of our patients was born to a consanguineous couple; in a subsequent pregnancy, real-time ultrasonography in the second trimester showed that the female fetus had the same abnormalities as its sib. Diagnosis was confirmed after elective abortion. This suggests that this short-rib syndrome may be an autosomal recessive disorder.     

Cardio-Facio-cutaneous (CFC) syndrome: Report of two patients without hyperkeratotic skin lesions

We report on two boys with the cardio-facio-cutaneous (CFC) syndrome, but without hyperkeratotic skin involvement. They showed most of the manifestations of the CFC syndrome: growth and developmental retardation, relative macrocephaly, distinct facial appearance, sparse hair, and heart defects. Their skin was not hyperkeratotic, but patient 1 had mild atopic dermatitis and keloid-like depigmented spots.     

Blepharophimosis,minor facial anomalies,genital anomalies,and mental retardation: Report of two sibs with a unique syndrome

We report on two sibs, a 2.5-year-old girl and a 10-month-old boy, with a hitherto unreported combination of congenital anomalies: blepharophimosis, ptosis, midface hypoplasia, abnormal palate, low anterior and posterior hairlines, displaced hair whorl, apparently low-set and abnormally shaped ears, trigonocephaly, dental anomalies, laryngomalacia, sensorineural hearing loss, genital anomalies, hypotonia, and mental retardation. The occurrence of a similar pattern of anomalies in two sibs of opposite sex suggests autosomal recessive inheritance. To our knowledge, this combination of anomalies has not been reported previously, and thus we propose it to be a formal genesis syndrome. Am. J. Med. Genet. 87:78–81, 1999. © 1999 Wiley-Liss, Inc.     

Report on two patients with Costello syndrome and sialuria

We report on 2 unrelated patients with Costello syndrome. The first is a 5-year-old girl with “coarse” face, nasal papillomata, redundant skin of feet and hands, hyperextensible hand and finger joints, curly hair, feeding problems due to oral motor apraxia, growth and psychomotor retardation. The second is a 3-year-old boy with “coarse” face, loose skin on hands and feet, curly hair, oral motor apraxia, severe growth and psychomotor retardation. In both patients urine sialic acid levels were found to be repeatedly high. The meaning of this biochemical abnormality is discussed. © 1993 Wiley-Liss, Inc.