Teratogen update: maternal myasthenia gravis as a cause of congenital arthrogryposis

Pregnancy in myasthenia gravis: a retrospective analysis of maternal and neonatal outcome from a large tertiary care centre in Germany

PURPOSE

Myasthenia gravis (MG) is a rare, potentially life-threatening autoimmune disease with fluctuating muscle weakness frequently affecting women of childbearing age. MG can affect maternal as well as neonatal outcome with risk of worsening of myasthenic symptoms in the mothers and risk of transient neonatal myasthenia gravis (TNMG) and arthrogryposis multiplex congenita (AMC) or foetal acetylcholine receptor antibody-associated disorders (FARAD) in the neonates.

METHODS

Retrospective analysis of maternal and neonatal outcome in a cohort of pregnant MG patients treated at a tertiary care centre in Germany.

RESULTS

Overall, 66 pregnancies were analysed. During 40 (63%) pregnancies, women experienced a worsening of myasthenic symptoms, of whom 10 patients (15.7%) needed acute therapy with IVIg or plasma exchange. There was no case of myasthenic crisis. Rate of caesarean section was comparable to the overall C-section rate at our centre (38% vs. 40%). However, there was a slightly higher rate for operative vaginal delivery (15% vs. 10%) as potential indicator for fatiguing striated musculature in MG patients during the expulsion stage. Rate of TNMG as well as AMC was 3% (two cases each).

CONCLUSIONS

Maternal and neonatal outcome in our cohort was favourable with a low rate of myasthenic exacerbations requiring acute therapies and a low rate of TNMG and AMC/FARAD. Our data might help neurologists and obstetricians to advice MG patients with desire to have children.

Myasthenia gravis and pregnancy: Lessons learned from a complex a case report

Myasthenia gravis primarily affects young adults, with a higher incidence in women, particularly between the ages of 20 and 30. When a young woman with myasthenia gravis contemplates pregnancy, healthcare providers must consider the potential implications. The interplay between hormonal factors and changes in the immune system establishes a complex relationship between myasthenia gravis and pregnancy. On one hand, pregnancy can alter the course of the disease, while on the other hand, the disease can impact the progression of the pregnancy and the well-being of the fetus. In this case report, we present the case of a 28-year-old woman suffering from myasthenia gravis who had undergone a thymectomy 5 years ago and was being treated with an acetylcholinesterase inhibitor. After a planned conception, the patient presented a relapse of her disease during the third trimester of pregnancy, with the onset of severe hydramnios. This observation highlights a specific case of decompensation of myasthenia gravis during pregnancy, associated with the presence of severe hydramnios. Subsequently, we delve into the existing literature to examine the reciprocal influence between myasthenia gravis and pregnancy, as well as the effects of anti-myasthenic treatments on pregnancy outcomes.

Transient Neonatal Myasthenia Gravis as a Common Complication of a Rare Disease: A Systematic Review

Myasthenia gravis (MG) is a rare autoimmune disease. Transient neonatal myasthenia gravis (TNMG) is caused by pathogenic maternal autoantibodies that cross the placenta and disrupt signaling at the neuromuscular junction. This is a systematic review of this transient immunoglobulin G (IgG)-mediated disease. TNMG affects 10-20% of children born to mothers with MG. The severity of symptoms ranges from minor feeding difficulties to life-threatening respiratory weakness. Minor symptoms might go unnoticed but can still interfere with breastfeeding. Acetylcholine-esterase inhibitors and antibody-clearing therapies such as immunoglobulins can be used to treat TNMG, but most children do well with observation only. TNMG is self-limiting within weeks as circulating antibodies are naturally cleared from the blood. In rare cases, TNMG is associated with permanent skeletal malformations or permanent myopathy. The mother's antibodies can also lead to spontaneous abortions. All healthcare professionals meeting pregnant or birthing women with MG or their neonates should be aware of TNMG. TNMG is hard to predict. Reoccurrence is common among siblings. Pre-pregnancy thymectomy and intravenous immunoglobulins during pregnancy reduce the risk. Neonatal fragment crystallizable receptor (FcRn) blocking drugs for MG might reduce TNMG risk.

Survival in Mudejar Spain in the Middle Ages (thirteenth-fourteenth centuries): Ancient Rare Diseases-an uncommon diagnosis in archaeological human remains

PURPOSE

The finding of severe skeletal alterations in ancient remains could give us useful information not only about the pathologies of the individual per se, as it could infer the state of health of a population.

METHODS

From the findings of the Mudéjar Cemetery of Uceda (Guadalajara, Central Spain) where a total of 116 burials with almost complete skeleton were recovered, an interesting individual is presented (palaeopathological perspective). The individual 114UC corresponds to a male of 20-25 years old and its age goes back to the thirteenth-fourteenth centuries.

RESULTS

The first inspection showed the presence of serious alterations especially in the lumbar spine and pelvic girdle. Seven vertebrae (from T11 to L5) showed an unusual posterior fusion only in the postzygapophyseal joints. The pelvis, after being accurately assembled and congruence verified by X-ray and CT scan, showed a noticeable asymmetry of both iliac wings together with a coxa magna protusa (Otto's pelvis), severe anteversion of both cup hips and osteochondritis of the right femoral head. The posterior-slope of both tibias reached about 10°.

CONCLUSIONS

The differential diagnoses lead us to think of Arthrogryposis Multiplex Congenita as the most probable diagnosis. We analyzed the same biomechanical aspects after taking into account some patterns that give us information about a possible mobility in the first stage of life. We discuss the very few other cases described both from artworks and in the palaeopathological record. To our knowledge, this case could be the oldest published case of AMC worldwide.

The emerging spectrum of fetal acetylcholine receptor antibody-related disorders (FARAD)

In utero exposure to maternal antibodies targeting the fetal acetylcholine receptor isoform (fAChR) can impair fetal movement, leading to arthrogryposis multiplex congenita (AMC). Fetal AChR antibodies have also been implicated in apparently rare, milder myopathic presentations termed fetal acetylcholine receptor inactivation syndrome (FARIS). The full spectrum associated with fAChR antibodies is still poorly understood. Moreover, since some mothers have no myasthenic symptoms, the condition is likely underreported, resulting in failure to implement effective preventive strategies. Here we report clinical and immunological data from a multicentre cohort (n = 46 cases) associated with maternal fAChR antibodies, including 29 novel and 17 previously reported with novel follow-up data. Remarkably, in 50% of mothers there was no previously established myasthenia gravis (MG) diagnosis. All mothers (n = 30) had AChR antibodies and, when tested, binding to fAChR was often much greater than that to the adult AChR isoform. Offspring death occurred in 11/46 (23.9%) cases, mainly antenatally due to termination of pregnancy prompted by severe AMC (7/46, 15.2%), or during early infancy, mainly from respiratory failure (4/46, 8.7%). Weakness, contractures, bulbar and respiratory involvement were prominent early in life, but improved gradually over time. Facial (25/34; 73.5%) and variable peripheral weakness (14/32; 43.8%), velopharyngeal insufficiency (18/24; 75%) and feeding difficulties (16/36; 44.4%) were the most common sequelae in long-term survivors. Other unexpected features included hearing loss (12/32; 37.5%), diaphragmatic paresis (5/35; 14.3%), CNS involvement (7/40; 17.5%) and pyloric stenosis (3/37; 8.1%). Oral salbutamol used empirically in 16/37 (43.2%) offspring resulted in symptom improvement in 13/16 (81.3%). Combining our series with all previously published cases, we identified 21/85 mothers treated with variable combinations of immunotherapies (corticosteroids/intravenous immunoglobulin/plasmapheresis) during pregnancy either for maternal MG symptom control (12/21 cases) or for fetal protection (9/21 cases). Compared to untreated pregnancies (64/85), maternal treatment resulted in a significant reduction in offspring deaths (P < 0.05) and other complications, with treatment approaches involving intravenous immunoglobulin/ plasmapheresis administered early in pregnancy most effective. We conclude that presentations due to in utero exposure to maternal (fetal) AChR antibodies are more common than currently recognized and may mimic a wide range of neuromuscular disorders. Considering the wide clinical spectrum and likely diversity of underlying mechanisms, we propose 'fetal acetylcholine receptor antibody-related disorders' (FARAD) as the most accurate term for these presentations. FARAD is vitally important to recognize, to institute appropriate management strategies for affected offspring and to improve outcomes in future pregnancies. Oral salbutamol is a symptomatic treatment option in survivors.

Transient Neonatal Myasthenia Gravis: A Case Report

Transient neonatal myasthenia gravis (TNMG) is a neuromuscular disorder that occurs in infants born from mothers with myasthenia gravis (MG) due to transplacental transfer of antibodies against the acetylcholine receptor. TNMG is a rare form occurring in 10-15% of infants born from mothers with MG. We present a case of a newborn with TNMG with generalized hypotonia and respiratory distress. The newborn shows symptoms of hypotonia, weakened reflexes, poor crying, difficult sucking and potentiated tachydyspnea after 24 hours of birth and needs of assisted mechanical ventilation. Based on the mother's positive history of MG and the high titer of mother's (8.43nmol/l) and newborn's (9.088nmol/l) anti-AChR antibodies, TNMG was diagnosed. The baby was treated with assisted mechanical ventilation and neostig-mine until the anti-AChR antibody titer was negative. Adequate management of the newborn resulted in a positive outcome and evident withdrawal of the symptoms. Although TNMG is one of the rare neuromuscular disorders in newborns that can be treated, a multidisciplinary approach in the management of pregnant women with MG and newborns through timely diagnosis and early appropriate treatment, results in successful resolution of this condition.

Diagnostic workup in children with arthrogryposis: description of practices from a single reference centre, comparison with literature and suggestion of recommendations

INTRODUCTION

Arthrogryposis multiplex congenita (AMC) refers to a clinical presentation of congenital contractures involving two or more body areas. More than 400 distinct conditions may lead to AMC, making the aetiological diagnosis challenging. The objective of this work was to set up evidence-based recommendations for the diagnosis of AMC by taking advantage of both data from our nation-wide cohort of children with AMC and from the literature.

MATERIAL AND METHODS

We conducted a retrospective single-centre observational study. Patients had been evaluated at least once at a paediatric age in the AMC clinic of Grenoble University Hospital between 2007 and 2019. After gathering data about their diagnostic procedure, a literature review was performed for each paraclinical investigation to discuss their relevance.

RESULTS

One hundred and twenty-five patients were included, 43% had Amyoplasia, 27% had distal arthrogryposis and 30% had other forms. A definitive aetiological diagnosis was available for 66% of cases. We recommend a two-time diagnostic process: first, non-invasive investigations that aim at classifying patients into one of the three groups, and second, selected investigations targeting a subset of patients.

CONCLUSION

The aetiological management for patients with AMC remains arduous. This process will be facilitated by the increasing use of next-generation sequencing combined with detailed phenotyping. Invasive investigations should be avoided because of their limited yield.

Fetal Surveillance in Pregnancies with Myasthenia Gravis

Myasthenia gravis (MG) is an autoimmune condition, that commonly impacts adult women of reproductive age. Myasthenia gravis in pregnancy is rare, but the incidence is higher in different geographical areas. Pregnancies in mothers with MG can have an unfortunate outcome. Acetylcholine receptor antibodies may pass into the fetal circulation and can affect the fetal neuromuscular junction, generating transient MG or even fetal arthrogryposis. The 2016 and 2021 International Consensus Guidance for Management of Myasthenia Gravis issued by Myasthenia Gravis Foundation of America is lacking in recommendation for fetal surveillance for pregnancies in women with MG. The aim of this paper is to highlight fetal and neonatal complications in mothers with MG and to offer antenatal care insights. Close maternal and pregnancy monitoring can improve pregnancy outcome. Patients with MG should be encouraged to conceive, to avoid triggers for exacerbations of the disease during pregnancy and a multidisciplinary team should be established to ensure the optimal support and therapy.

Clinical and pathophysiologic relevance of autoantibodies in neonatal myasthenia gravis

Between 10% and 20% of neonates born to mothers with myasthenia gravis (MG) develop neonatal MG due to the transfer of maternal autoantibodies across the placenta. Neonatal MG can occur in infants born not only from mothers with acetylcholine receptor (AChR) or muscle-specific tyrosine kinase (MuSK) antibodies but also from mothers without detectable muscle antibodies. The low incidence rate may be due to specific autoantibody characteristics that differ among individuals, but a genetic predisposition in some infants is possible. The majority of reported neonatal MG cases are anti-AChR antibody-positive (AChR-MG), and a high anti-fetal/anti-adult AChR titer ratio in the mother is predictive of its occurrence. However, patients with anti-MuSK antibody-positive MG (MuSK-MG) are more likely to experience exacerbations during pregnancy and have a higher probability of developing neonatal MG than AChR-MG patients. Moreover, maternal MuSK-MG may be associated with early-onset and more severe manifestations of neonatal MG. Although cholinesterase inhibitors have been effectively used for treating neonatal AChR-MG, neonatal MuSK-MG may be more difficult to treat with this type of medication. Maternal MuSK-MG usually greatly benefits from intravenous immunoglobulin (IVIG) and plasma exchange. In neonatal MG, IVIG is considered for severely affected infants with MuSK-MG, but the efficacy of IVIG remains unclear. Although exchange transfusion may be a management adjunct, its clinical benefits are controversial. As the therapy-induced reduction of autoantibodies may be advantageous for fetal outcomes, maternal MG should be effectively treated during pregnancy. However, caution of drug contraindication during pregnancy and lactation must be exercised to avoid unwanted effects for the fetus and neonate. In the future, MG caused by anti-lipoprotein receptor-related protein 4 or other antibodies might be also identified in pregnant women and neonates. Therefore, the determination of autoantibody specificity is essential for successful management.

Myasthenia Gravis and Pregnancy: Toronto Specialty Center Experience

BACKGROUND

Myasthenia gravis (MG) is an autoimmune disorder that frequently affects young women of reproductive age. The multidirectional interplay between MG, pregnancy, and fetal health poses a complex scenario for pregnant women with MG and the healthcare team. Here, we reviewed our local experience with MG, pregnancy, and outcomes.

METHODS

We performed a retrospective chart review of patients with MG attending the Prosserman Family Neuromuscular Clinic from 2001 to 2019 and who were referred to a high-risk pregnancy clinic. MG status was defined as stable, better, or worse. Information was collected on the delivery route, pregnancy, and neonatal complications.

RESULTS

We identified 20 women with MG for a total of 28 pregnancies. Worsening was observed in 50% of pregnancies: 18% during pregnancy, 25% following delivery, and 7% during both. 66.7% of patients with MG duration of 2 years or less had worsening during pregnancy. Three patients who stopped immunosuppressive treatment during pregnancy worsened and one had a crisis. C-section was done in 29% of pregnancies. The rate of delivery complications was 7% and of neonatal MG was 7%.

CONCLUSION

A high proportion of MG patients worsened during pregnancy, particularly those with disease duration less than 2 years, and those who discontinued immunosuppression during pregnancy. However, pregnancy was largely unaffected, rate of neonatal MG was low, frequencies of C-section, delivery complications, and premature births were similar to the general population. While the study has limitations due to the retrospective nature, these insights provide some guidance when counseling young myasthenic women about family planning.

Myasthaenia gravis in pregnancy, delivery and newborn

INTRODUCTION

Myasthaenia gravis (MG) is the most common disease of the neuromuscular junction; clinical presentation of the disease includes a variety of symptoms, the most frequent beign the only ocular muscles involvement, to the generalized myasthenic crisis with diaphragmatic impairment and respiratory insufficiency. It is most common in women between 20 ad 40 years.

EVIDENCE ACQUISITION

We performed a comprehensive search of relevant studies from January1990 to Dicember 2019 to ensure all possible studies were captured. A systematic search of Pubmed databases was conducted.

EVIDENCE SYNTHESIS

Pregnancy has an unpredictable and variable effect on the clinical course of MG; however, a stable disease before is likely not to relapse during pregnancy. exacerbations can still occur more often during the first trimester and the post partum period. The transplacental passage of antibodies results in a neonatal transient disease, whereas the major concern is related to foetal malformations such as fetal arthrogryposis and polyhydramnios. The overall neonatal outcome described in literature is variable, perinatal mortality in women with MG is generally the same as non affected patients, although in one study the risk of premature rupture of the membranes was higher. Treatment of MG in pregnangncy includes pyridostigmine and corticosteroids, although the latter have been associated with higher risk of cleft palate, premature rupture of the membranes and preterm delivery. These drugs appear also to be safe in breastfeeding. In MG patients spontaneous vaginal delivery should be encouraged, for surgery could cause acute worsening of myasthenic symptoms; also an accurate anesthesiological evaluation must be performed prior to both general and local anesthesia due to increased risk of complications.

CONCLUSIONS

Most of the myasthenic women could have uneventful pregnancy with good obstetrical outcomes, both for mother and neonate. However, a careful planning of pregnancy and multidisciplinary team approach, composed by neurologists, obstetricians, neonatologists and anesthesiologists, is required to manage these pregnancies.

Prognostic significance of prenatal ultrasound in fetal arthrogryposis multiplex congenita

Purpose

Fetal arthrogryposis multiplex congenita (AMC) describes a heterogeneous disease entity characterized by multiple contractures affecting at least two different body areas. The aim of our study was to identify additional sonographic abnormalities in fetuses with AMC Type I–III associated with an unfavorable prognosis and to describe when those signs were first detected.

Methods

This retrospective study included 41 pregnancies of suspected AMC diagnosed 1999–2017 at our tertiary referral center. The affected pregnancies were divided into the 3 AMC subgroups; the time of detection and outcome were analyzed. Prenatal sonograms, pediatric charts, genetic tests, and autopsy reports were studied.

Results

Pregnancy outcome data were verifiable in 34 out of 41 cases; in 27 cases, AMC was confirmed. Hydrops was present in 50% of postnatally deceased fetuses, 53% of cases resulting in termination of pregnancy vs. 0% of the surviving 8 children. Absent stomach filling was found in 67% of the children with neonatal death. After subcategorization, the limb-involvement-only-group, 8% showed hydrops vs. 100% in system anomaly group vs. 70% in neuromuscular dysfunction cohort (p = 0.001). Scoliosis, nuchal edema, and absent stomach filling were significantly indicating for a neurological etiology.

Conclusion

In addition to disease-defining sonographic findings, those with prognostic significance were identified. Hydrops, nuchal edema, scoliosis and absent stomach filling were associated with unfavorable outcomes implicating a neuromuscular etiology. This knowledge can help to predict the further course of the disease and support patient counseling.

Myasthenia gravis and pregnancy

Myasthenia gravis (MG) is an autoimmune disorder with bimodal age of presentation, occurring in young women of reproductive age and at an older age in men. Occasionally, MG is diagnosed during pregnancy. Management of MG includes symptomatic treatment with cholinesterase inhibitors and immunosuppressive therapy for controlling the disease activity. Treatment of MG in women of reproductive age, who may be contemplating pregnancy, requires discussion regarding the choice of medication as well as the understanding of risks/adverse effects involved with various treatments. During the peripartum period, it is essential to ensure careful monitoring of the disease state along with the well-being of the mother and fetus and to coordinate neonatal monitoring overseen by a multidisciplinary team comprising a high-risk maternal fetal medicine specialist, a neurologist familiar with these complex issues, and a neonatologist.

Fetal arthrogryposis: Challenges and perspectives for prenatal detection and management

Antenatal identification of fetuses with multiple congenital contractures or arthrogryposis multiplex congenita (AMC) may be challenging. The first clinical sign is often reduced fetal movement and/or contractures, as seen on prenatal ultrasounds. This can be apparent at any point, from early to late pregnancy, may range from mild to severe involvement, with or without associated other structural anomalies. Possible etiologies and their prognosis need to be interpreted with respect to developmental timing. The etiology of AMC is highly heterogeneous and making the specific diagnosis will guide prognosis, counseling and prenatal and perinatal management. Current ultrasound practice identifies only approximately 25% of individuals with arthrogryposis prenatally before 24 weeks of pregnancy in a general obstetrics care population. There are currently no studies and guidelines that address the question of when and how to assess for fetal contractures and movements during pregnancy. The failure to identify fetuses with arthrogryposis before 24 weeks of pregnancy means that physicians and families are denied reproductive options and interventions that may improve outcome. We review current practice and recommend adjusting the current prenatal imaging and genetic diagnostic strategies to achieve early prenatal detection and etiologic diagnosis. We suggest exploring options for in utero therapy to increase fetal movement for ongoing pregnancies.

Fetal arthrogryposis multiplex congenita/fetal akinesia deformation sequence (FADS)-Aetiology, diagnosis, and management

Arthrogryposis multiplex congenita (AMC) refers to an aetiologically heterogenous condition, which consists of joint contractures affecting two or more joints starting prenatally. The incidence is approximately one in 3000 live births; however, the prenatal incidence is higher, indicating a high intrauterine mortality. Over 320 genes have been implicated showing the genetic heterogeneity of the condition. AMC can be of extrinsic aetiology resulting from intrauterine crowding secondary to congenital structural uterine abnormalities (eg, bicornuate or septate uterus), uterine tumors (eg, fibroid), or multifetal pregnancy or intrinsic/primary/fetal aetiology, due to functional abnormalities in the brain, spinal cord, peripheral nerves, neuromuscular junction, muscles, bones, restrictive dermopathies, tendons and joints. Unlike many of the intrinsic/primary/fetal causes which are difficult to treat, secondary AMC can be treated by physiotherapy with good response. Primary cases may present prenatally with fetal akinesia associated with joint contractures and occasionally brain abnormalities, decreased muscle bulk, polyhydramnios, and nonvertex presentation while the secondary cases usually present with isolated contractures. Complete prenatal and postnatal investigations are needed to identify an underlying aetiology and provide information regarding its prognosis and inheritance, which is critical for the obstetrical care providers and families to optimize the pregnancy management and address future reproductive plans.

Rare etiology of arthrogryposis multiplex congenita at term: congenital cytomegalovirus infection

Background

Arthrogryposis multiplex congenita is the presence of multiple congenital contractures of two or more body parts. Congenital cytomegalovirus (CMV) infection is a rare etiology of arthrogryposis.

Case presentation

We report a case of intrauterine fetal akinesia and arthrogryposis multiplex congenita delivered at term with subsequent neonatal demise. Placental pathology and autopsy revealed congenital CMV infection.

Conclusions

Evaluation for potential CMV infection is an important part of the arthrogryposis evaluation which is often missed due to lack of maternal infectious symptoms during pregnancy.

Characterization of an anti-fetal AChR monoclonal antibody isolated from a myasthenia gravis patient

We report here the sequence and functional characterization of a recombinantly expressed autoantibody (mAb 131) previously isolated from a myasthenia gravis patient by immortalization of thymic B cells using Epstein-Barr virus and TLR9 activation. The antibody is characterized by a high degree of somatic mutations as well as a 6 amino acid insertion within the VHCDR2. The recombinant mAb 131 is specific for the γ-subunit of the fetal AChR to which it bound with sub-nanomolar apparent affinity, and detected the presence of fetal AChR on a number of rhabdomyosarcoma cell lines. Mab 131 blocked one of the two α-bungarotoxin binding sites on the fetal AChR, and partially blocked the binding of an antibody (mAb 637) to the α-subunit of the AChR, suggesting that both antibodies bind at or near one ACh binding site at the α/γ subunit interface. However, mAb 131 did not reduce fetal AChR ion channel currents in electrophysiological experiments. These results indicate that mAb 131, although generated from an MG patient, is unlikely to be pathogenic and may make it a potentially useful reagent for studies of myasthenia gravis, rhabdomyosarcoma and arthrogryposis multiplex congenita which can be caused by fetal-specific AChR-blocking autoantibodies.

Myasthaenia Gravis: Clinical management issues before, during and after pregnancy

Myasthaenia gravis (MG) is an autoimmune neuromuscular disorder which is twice as common among women, often presenting in the second and third decades of life. Typically, the first trimester of pregnancy and first month postpartum are considered high-risk periods for MG exacerbations. During pregnancy, treatment for MG is usually individualised, thus improving its management. Plasma exchange and immunoglobulin therapies can be safely used to treat severe manifestations of the disease or myasthaenic crises. However, thymectomies are not recommended because of the delayed beneficial effects and possible risks associated with the surgery. Assisted vaginal delivery-either vacuum-assisted or with forceps-may be required during labour, although a Caesarean section under epidural anaesthesia should be reserved only for standard obstetric indications. Myasthaenic women should not be discouraged from attempting to conceive, provided that they seek comprehensive counselling and ensure that the disease is under good control before the start of the pregnancy.

Maternal autoimmune disorders and fetal defects

Maternal autoantibodies can cross the placenta and cause fetal damage. This article summarizes the development and management of fetal thyroid goiter in response to maternal Graves' disease and/or its treatment with antithyroid medication, fetal heart block due to maternal anti-Ro and anti-La antibodies, fetal athrogryposis multiplex congenita in association with maternal myasthenia gravis and fetal brain hemorrhage due to maternal autoimmune thrombocytopenia.

Maternal myasthenia gravis: a cause for arthrogryposis multiplex congenita

BACKGROUND

Arthrogryposis multiplex congenita (AMC) is a condition defined as contractures in more than two joints and in multiple body areas. The principal mechanism leading to the development of AMC in utero is decreased fetal movement.

OBJECTIVE

Both fetal and maternal factors can lead to this condition, including maternal myasthenia gravis (MG) which is the topic of this review. MG is an autoimmune disease in which antibodies (immunoglobulin G) are formed against acetylcholine receptors. The disease can affect both genders, but women are more prone to develop the disease in early adulthood, a phase of life when the focus of many women is often directed towards founding a family. During pregnancy, maternal antibodies are transmitted to the fetus.

RESULTS

Although the child is unaffected in most cases, the constant transmission of antibodies in utero can lead to neonatal myasthenia post-partum, a transient condition characterized by hypotonia and swallowing/respiratory difficulties as well as AMC.

CONCLUSION

The maternal antibody profile in mothers with MG seems to play a key role in whether the child develops AMC or not. There are also indications that there may be a relation between neonatal MG and AMC, as well as a high recurrence rate in siblings.

ECEL1 mutation causes fetal arthrogryposis multiplex congenita

Arthrogryposis multiplex congenita (AMC) is a descriptor for the clinical finding of congenital fixation of multiple joints. We present a consanguineous healthy couple with two pregnancies described with AMC due to characteristic findings on ultrasonography of fixated knee extension and reduced fetal movement at the gestational age of 13 weeks + 2 days and 12 weeks + 4 days. Both pregnancies were terminated and postmortem examinations were performed. The postmortem examinations confirmed AMC and suggested a diagnosis of centronuclear myopathy (CNM) due to characteristic histological findings in muscle biopsies. Whole exome sequencing (WES) was performed on all four individuals and the outcome was filtered by application of multiple filtration parameters satisfying a recessive inheritance pattern. Only one gene, ECEL1, was predicted damaging and had previously been associated with neuromuscular disease or AMC. The variant found ECEL1 is a missense mutation in a highly conserved residue and was predicted pathogenic by prediction software. The finding expands the molecular basis of congenital contractures and the phenotypic spectrum of ECEL1 mutations. The histological pattern suggestive of CNM in the fetuses can expand the spectrum of genes causing CNM, as we propose that mutations in ECEL1 can cause CNM or a condition similar to this. Further investigation of this is needed and we advocate that future patients with similar clinical presentation or proven ECEL1 mutations are examined with muscle biopsy. Secondly, this study illustrates the great potential of the clinical application of WES in couples with recurrent abortions or stillborn neonates.

Plant alkaloids that cause developmental defects through the disruption of cholinergic neurotransmission

The exposure of a developing embryo or fetus to alkaloids from plants, plant products, or plant extracts has the potential to cause developmental defects in humans and animals. These defects may have multiple causes, but those induced by piperidine and quinolizidine alkaloids arise from the inhibition of fetal movement and are generally referred to as multiple congenital contracture-type deformities. These skeletal deformities include arthrogyrposis, kyposis, lordosis, scoliosis, and torticollis, associated secondary defects, and cleft palate. Structure-function studies have shown that plant alkaloids with a piperidine ring and a minimum of a three-carbon side-chain α to the piperidine nitrogen are teratogenic. Further studies determined that an unsaturation in the piperidine ring, as occurs in gamma coniceine, or anabaseine, enhances the toxic and teratogenic activity, whereas the N-methyl derivatives are less potent. Enantiomers of the piperidine teratogens, coniine, ammodendrine, and anabasine, also exhibit differences in biological activity, as shown in cell culture studies, suggesting variability in the activity due to the optical rotation at the chiral center of these stereoisomers. In this article, we review the molecular mechanism at the nicotinic pharmacophore and biological activities, as it is currently understood, of a group of piperidine and quinolizidine alkaloid teratogens that impart a series of flexure-type skeletal defects and cleft palate in animals.

Autoimmune myasthenia gravis

Myasthenia gravis in children can be generalized or ocular, and associated with antibodies to acetylcholine receptors or muscle-specific kinase, but it can be negative for those antibodies (seronegative). It needs to be distinguished from congenital myasthenic syndromes and other neuromuscular diseases. In the perinatal period, transient neonatal myasthenia and arthrogryposis multiplex congenita, due to maternal antibodies, need to be considered. Juvenile myasthenia is similar in presentation and treatment to that in adults. Here we present guidelines for recognition, diagnosis, and treatment.

Pregnancy and myasthenia gravis

PURPOSE OF REVIEW

Myasthenia gravis (MG) is an acquired autoimmune disorder characterized by fluctuating ocular, limb, or oropharyngeal muscle weakness due to an antibody-mediated attack at the neuromuscular junction. The female incidence of MG peaks in the third decade during the childbearing years. A number of exacerbating factors may worsen MG, including pregnancy. When treatment is needed, it must be carefully chosen with consideration of possible effects on the mother with MG, the pregnancy, and the fetus.

RECENT FINDINGS

Decisions are complex in the treatment of women with MG contemplating pregnancy or with presentation during pregnancy. While data is largely observational, a number of characteristic patterns and issues related to risk to the patient, integrity of the pregnancy, and risks to the fetus are recognized. Familiarity with these special considerations when contemplating pregnancy is essential to avoid potential hazards in both the patient and the fetus. Use of immunosuppressive agents incurs risk to the fetus. Deteriorating MG with respiratory insufficiency poses risk to both the mother and the fetus.

SUMMARY

This article reviews available information regarding expectations and management for patients with MG in the childbearing age. Treatment decisions must be individualized based on MG severity, distribution of weakness, coexisting diseases, and welfare of the fetus. Patient participation in these decisions is essential for successful management.

Clonal heterogeneity of thymic B cells from early-onset myasthenia gravis patients with antibodies against the acetylcholine receptor

Myasthenia gravis (MG) with antibodies against the acetylcholine receptor (AChR-MG) is considered as a prototypic autoimmune disease. The thymus is important in the pathophysiology of the disease since thymus hyperplasia is a characteristic of early-onset AChR-MG and patients often improve after thymectomy. We hypothesized that thymic B cell and antibody repertoires of AChR-MG patients differ intrinsically from those of control individuals. Using immortalization with Epstein-Barr Virus and Toll-like receptor 9 activation, we isolated and characterized monoclonal B cell lines from 5 MG patients and 8 controls. Only 2 of 570 immortalized B cell clones from MG patients produced antibodies against the AChR (both clones were from the same patient), suggesting that AChR-specific B cells are not enriched in the thymus. Surprisingly, many B cell lines from both AChR-MG and control thymus samples displayed reactivity against striated muscle proteins. Striational antibodies were produced by 15% of B cell clones from AChR-MG versus 6% in control thymus. The IgVH gene sequence analysis showed remarkable similarities, concerning VH family gene distribution, mutation frequency and CDR3 composition, between B cells of AChR-MG patients and controls. MG patients showed clear evidence of clonal B cell expansion in contrast to controls. In this latter aspect, MG resembles multiple sclerosis and clinically isolated syndrome, but differs from systemic lupus erythematosus. Our results support an antigen driven immune response in the MG thymus, but the paucity of AChR-specific B cells, in combination with the observed polyclonal expansions suggest a more diverse immune response than expected.

Diagnosing arthrogryposis multiplex congenita: a review

Arthrogryposis multiplex congenita (AMC) refers either to a syndromic or to a nonsyndromic group of conditions with varied etiology and complex clinical features, including multiple congenital contractures in different body areas. Its etiology still remains unclear but generally any cause that leads to reduced fetal movement may lead to congenital contractures and in severe cases to fetal akinesia deformation sequence (FADS). It affects approximately 1 in 2-3000 live births with an approximately equal gender ratio. There are many known subgroups of AMC differing in signs, symptoms, and causes. The primary diagnosis is made when a lack of mobility and an abnormal position is noted in routine ultrasound scanning. Early diagnosis, prenatal evaluation, and further surveillance via image scanning (ultrasound and MRI) give the opportunity for family counseling concerning neonatal morbidity and mortality and labor or delivery planning. Better understanding of the ultrasound findings and the etiology of this clinical situation offers the opportunity for careful prenatal assessment.

Piperidine alkaloids: human and food animal teratogens

Piperidine alkaloids are acutely toxic to adult livestock species and produce musculoskeletal deformities in neonatal animals. These teratogenic effects include multiple congenital contracture (MCC) deformities and cleft palate in cattle, pigs, sheep, and goats. Poisonous plants containing teratogenic piperidine alkaloids include poison hemlock (Conium maculatum), lupine (Lupinus spp.), and tobacco (Nicotiana tabacum) [including wild tree tobacco (Nicotiana glauca)]. There is abundant epidemiological evidence in humans that link maternal tobacco use with a high incidence of oral clefting in newborns; this association may be partly attributable to the presence of piperidine alkaloids in tobacco products. In this review, we summarize the evidence for piperidine alkaloids that act as teratogens in livestock, piperidine alkaloid structure-activity relationships and their potential implications for human health.

Myasthenia gravis: a review of available treatment approaches

Patients with autoimmune myasthenia gravis (MG) should be further classified before initiating therapy, as treatment response varies for ocular versus generalised, early onset versus late onset, and acetylcholine receptor antibody positive versus MuSK antibody positive disease. Most patients need immunosuppression in addition to symptomatic therapy. Prednisolone and azathioprine represent first choice drugs, whereas several second choice options are recommended and should be considered. Thymectomy should be undertaken in MG with thymoma and in generalised, early-onset MG. For MG crises and other acute exacerbations, intravenous immunoglobulin (IvIg) and plasma exchange are equally effective and safe treatments. Children and females in child bearing age need special attention regarding potential side effects of immunosuppressive therapy. MG pathogenesis is known in detail, but the immune therapy is still surprisingly unspecific, without a pin-pointed attack on the defined disease-inducing antigen-antibody reaction being available.

Autoantibodies in neuromuscular transmission disorders

It is a great pleasure to be asked to honour the memory of Dr. Baldev Singh by reviewing the field of autoantibodies in myasthenia gravis and other neurotransmission disorders. The neuromuscular junction (NMJ) is the site of a number of different autoimmune and genetic disorders, and it is also the target of many neurotoxins from venomous snakes, spiders, scorpions and other species. The molecular organization of the NMJ is graphically represented in Figure 1A, where different ion channels, receptors and other proteins are shown. Four of the ion channels or receptors are directly involved in autoimmune diseases. This brief review will not only concentrate on these conditions but also illustrate how their study is helping us to understand the etiology of rare but treatable neurological syndromes of the central nervous system.

[Course and treatment of myasthenia gravis during pregnancy]

Pregnancy and family planning issues are frequent concerns in the medical care of patients with myasthenia gravis since disease onset often coincides with the life period which is decisive in this respect. Although pregnancy, delivery and breastfeeding represent special circumstances in these patients, they are not associated with higher risks of complications compared to normal pregnancy, delivery and postpartum period. Frequently asked questions regard the course of pregnancy as well as the impact of the disease and particularly medical treatment on pregnancy and the foetus or neonate. Great significance is attached to the mode of delivery since it is still widely accepted that patients with myasthenia gravis have to deliver per elective caesarean section. This paper gives an overview and provides a basis for the medical care and individual counselling of patients with myasthenia gravis who want to start a family or are already pregnant.

Autoimmune channelopathies: well-established and emerging immunotherapy-responsive diseases of the peripheral and central nervous systems

BACKGROUND

The role of antibodies in neuromuscular junction disorders is well established with antibodies to acetylcholine receptor, muscle-specific kinase, and voltage-gated calcium channels. The diseases associated with these antibodies, myasthenia gravis and the Lambert-Eaton myasthenic syndrome, respond well to symptomatic treatments (e.g., cholinesterase inhibitors) and to immunotherapies such as plasma exchange, intravenous immunoglobulin, oral steroids, and steroid-sparing drugs. The role of the antibodies has been established by a variety of in vitro and in vivo approaches. More recently, antibodies to voltage-gated potassium channels have been identified in patients with autoimmune forms of acquired neuromyotonia. Over the last decade, antibodies to CNS membrane receptors or ion channels have begun to be identified and these antibodies define antibody-mediated CNS diseases that also respond to immunotherapies.

SUMMARY

The paradigms gained from the study of the peripheral conditions has led to a better appreciation of the role of antibodies in neurological disorders and a growing recognition of their role in central nervous system (CNS) diseases.

Mechanisms underlying autoimmune synaptic encephalitis leading to disorders of memory, behavior and cognition: insights from molecular, cellular and synaptic studies

Recently, several novel, potentially lethal and treatment-responsive syndromes that affect hippocampal and cortical function have been shown to be associated with auto-antibodies against synaptic antigens, notably glutamate or GABA-B receptors. Patients with these auto-antibodies, sometimes associated with teratomas and other neoplasms, present with psychiatric symptoms, seizures, memory deficits and decreased levels of consciousness. These symptoms often improve dramatically after immunotherapy or tumor resection. Here we review studies of the cellular and synaptic effects of these antibodies in hippocampal neurons in vitro and preliminary work in rodent models. Our work suggests that patient antibodies lead to rapid and reversible removal of neurotransmitter receptors from synaptic sites, leading to changes in synaptic and circuit function that in turn are likely to lead to behavioral deficits. We also discuss several of the many questions raised by these and related disorders. Determining the mechanisms underlying these novel anti-neurotransmitter receptor encephalopathies will provide insights into the cellular and synaptic bases of the memory and cognitive deficits that are hallmarks of these disorders, and potentially suggest avenues for therapeutic intervention.

Stereotypies and hyperactivity in rhesus monkeys exposed to IgG from mothers of children with autism

Autism together with Asperger syndrome and pervasive developmental disorder not otherwise specified form a spectrum of conditions (autism spectrum disorders or ASD) that is characterized by disturbances in social behavior, impaired communication and the presence of stereotyped behaviors or circumscribed interests. Recent estimates indicate a prevalence of ASD of 1 per 150 (Kuehn, 2007). The cause(s) of most cases of ASD are unknown but there is an emerging consensus that ASD have multiple etiologies. One proposed cause of ASD is exposure of the fetal brain to maternal autoantibodies during pregnancy [Dalton, P., Deacon, R., Blamire, A., Pike, M., McKinlay, I., Stein, J., Styles, P., Vincent, A., 2003. Maternal neuronal antibodies associated with autism and a language disorder. Ann. Neurol. 53, 533-537]. To provide evidence for this hypothesis, four rhesus monkeys were exposed prenatally to human IgG collected from mothers of multiple children diagnosed with ASD. Four control rhesus monkeys were exposed to human IgG collected from mothers of multiple typically developing children. Five additional monkeys were untreated controls. Monkeys were observed in a variety of behavioral paradigms involving unique social situations. Behaviors were scored by trained observers and overall activity was monitored with actimeters. Rhesus monkeys gestationally exposed to IgG class antibodies from mothers of children with ASD consistently demonstrated increased whole-body stereotypies across multiple testing paradigms. These monkeys were also hyperactive compared to controls. Treatment with IgG purified from mothers of typically developing children did not induce stereotypical or hyperactive behaviors. These findings support the potential for an autoimmune etiology in a subgroup of patients with neurodevelopmental disorders. This research raises the prospect of prenatal evaluation for neurodevelopmental risk factors and the potential for preventative therapeutics.

Acetylcholine receptor pathway mutations explain various fetal akinesia deformation sequence disorders

Impaired fetal movement causes malformations, summarized as fetal akinesia deformation sequence (FADS), and is triggered by environmental and genetic factors. Acetylcholine receptor (AChR) components are suspects because mutations in the fetally expressed gamma subunit (CHRNG) of AChR were found in two FADS disorders, lethal multiple pterygium syndrome (LMPS) and Escobar syndrome. Other AChR subunits alpha1, beta1, and delta (CHRNA1, CHRNB1, CHRND) as well as receptor-associated protein of the synapse (RAPSN) previously revealed missense or compound nonsense-missense mutations in viable congenital myasthenic syndrome; lethality of homozygous null mutations was predicted but never shown. We provide the first report to our knowledge of homozygous nonsense mutations in CHRNA1 and CHRND and show that they were lethal, whereas novel recessive missense mutations in RAPSN caused a severe but not necessarily lethal phenotype. To elucidate disease-associated malformations such as frequent abortions, fetal edema, cystic hygroma, or cardiac defects, we studied Chrna1, Chrnb1, Chrnd, Chrng, and Rapsn in mouse embryos and found expression in skeletal muscles but also in early somite development. This indicates that early developmental defects might be due to somite expression in addition to solely muscle-specific effects. We conclude that complete or severe functional disruption of fetal AChR causes lethal multiple pterygium syndrome whereas milder alterations result in fetal hypokinesia with inborn contractures or a myasthenic syndrome later in life.

Quantification of antineural antibodies in autoimmune neurological disorders

More than 50 different neurological pathologies have a confirmed or suspected autoimmune etiology affecting an estimated number of 75 million people worldwide. Autoantibodies are a useful diagnostic marker for most autoimmune diseases even though their pathological role is not evident, and several tests for their detection are commercially available. However, for autoimmune diseases involving the nervous system, lack of clear information on the identity of antineural antibody targets and the presence of many rare diseases have hampered the development of specific diagnostic assays. This review focuses on the actual knowledge on confirmed and suspected autoimmune diseases that target the CNS and the diagnostic relevance of corresponding antineural autoantibodies.

Bilateral periventricular nodular heterotopia with amniotic band syndrome

The amniotic (constriction) band syndrome is characterized by distal ring constrictions, intrauterine amputations, and acrosyndactyly. External constriction by amniotic bands is the generally accepted mechanism: early amniotic rupture leads to formation of mesodermal fibrous strands that constrict, entangle, and amputate distal portions of limbs. Etiology is heterogeneous. Anecdotal cases involving central nervous system abnormalities (e.g., acrania, anencephaly, polymicrogyria, congenital bilateral perisylvian syndrome, neuronal heterotopia, septo-optic dysplasia, and spinal cord tethering) have been reported. We describe a 9-year-old girl with typical features of constriction band syndrome localized to the lower limbs who had also profound mental retardation and drug-resistant epilepsy associated with bilateral periventricular nodular heterotopia (a brain malformation of neuronal migration and proliferation caused by mutations in the X-linked filamin 1 gene [FLN1] on chromosome Xq28). The karyotype was normal, as was mutational screening for FLN1. The occurrence of bilateral periventricular nodular heterotopia in the context of amniotic band syndrome is novel (chance occurrence of both: 0.000004%).