Analysis of Pena Shokeir phenotype

The Pena-Shokeir Syndrome in a Twin Pregnancy: A Rare Case Report

Pena-Shokeir Syndrome (PSS) is a rare autosomal recessive disorder characterized by dysmorphic features, camptodactyly, arthrogryposis, intrauterine growth restriction, polyhydramnios, and pulmonary hypoplasia. Two types of this syndrome have been defined, differentiated by distinct clinical and genetic features. PSS is a potentially life-threatening condition, with most cases expected to be diagnosed prenatally via ultrasound. Genetic counseling is crucial to inform parents about recurrence risks and management strategies for future pregnancies. We report a case of PSS in a dichorionic diamniotic (DCDA) twin pregnancy. Despite normal prenatal ultrasounds, 1 twin was diagnosed postnatally with severe craniofacial anomalies, limb deformities, and pulmonary complications, consistent with PSS. In contrast, the second twin exhibited normal growth and development, with no anomalies identified. To the best of our knowledge, this is the third reported case of PSS in a twin pregnancy and the second involving a normal co-twin. This case aims to contribute to the existing literature by detailing the unique dysmorphic and clinical findings associated with PSS and emphasizing the diagnostic challenges in twin pregnancies.

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.

Mechanical loading due to muscle movement regulates establishment of the collagen network in the developing murine skeleton

Mechanical loading is critical for collagen network maintenance and remodelling in adult skeletal tissues, but the role of loading in collagen network formation during development is poorly understood. We test the hypothesis that mechanical loading is necessary for the onset and maturation of spatial localization and structure of collagens in prenatal cartilage and bone, using in vivo and in vitro mouse models of altered loading. The majority of collagens studied was aberrant in structure or localization, or both, when skeletal muscle was absent in vivo. Using in vitro bioreactor culture system, we demonstrate that mechanical loading directly modulates the spatial localization and structure of collagens II and X. Furthermore, we show that mechanical loading in vitro rescues aspects of the development of collagens II and X from the effects of fetal immobility. In conclusion, our findings show that mechanical loading is a critical determinant of collagen network establishment during prenatal skeletal development.

Deformations associated with arthrogryposis

Fetal movement is essential to normal human development. If the fetus does not move for whatever reason, then multiple organs and organ systems develop secondary and tertiary effects not normally present. Most of these are deformations with secondary structural damage.

Embryonic movement stimulates joint formation and development: Implications in arthrogryposis multiplex congenita

Arthrogryposis multiplex congenita (AMC) is a heterogeneous syndrome where multiple joints have reduced range of motion due to contracture formation prior to birth. A common cause of AMC is reduced embryonic movement in utero. This reduction in embryonic movement can perturb molecular mechanisms and signaling pathways involved in the formation of joints during development. The absence of mechanical stimuli can impair joint cavitation, resulting in joint fusion, and ultimately eliminate function. In turn, mechanical stimuli are critical for proper joint formation during development and for mitigating AMC. Studies in experimental animal models have provided a greater understanding on the molecular pathophysiology of congenital contracture formation as a consequence of embryonic immobilization. Elucidation of how the mechanical signaling environment is transduced to initiate a biological response will be necessary to gain a deeper understanding of how mechanical stimuli are intertwined in the molecular regulation of joint development.

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.

Hoffman N, Kimber E, Komolkin I, Lester R, Pontén E, van Bosse HJP, Hall JG. International multidisciplinary collaboration toward an annotated definition of arthrogryposis multiplex congenita

Arthrogryposis multiplex congenita (AMC) has been described and defined in thousands of articles, but the terminology used has been inconsistent in clinical and research communities. A definition of AMC was recently developed using a modified Delphi consensus method involving 25 experts in the field of AMC from 8 countries. Participants included health care professionals, researchers, and individuals with AMC. An annotation of the definition provides more in-depth explanations of the different sentences of the AMC definition and is useful to complement the proposed definition. The aim of this study was to provide an annotation of the proposed consensus-based AMC definition. For the annotation process, 17 experts in AMC representing 10 disciplines across 7 countries participated. A paragraph was developed for each sentence of the definition using an iterative process involving multiple authors with varied and complementary expertise, ensuring all points of view were taken into consideration. The annotated definition provides an overview of the different topics related to AMC and is intended for all stakeholders, including youth and adults with AMC, their families, and clinicians and researchers, with the hopes of unifying the understanding of AMC in the international community.

Biallelic mutations in nucleoporin NUP88 cause lethal fetal akinesia deformation sequence

Nucleoporins build the nuclear pore complex (NPC), which, as sole gate for nuclear-cytoplasmic exchange, is of outmost importance for normal cell function. Defects in the process of nucleocytoplasmic transport or in its machinery have been frequently described in human diseases, such as cancer and neurodegenerative disorders, but only in a few cases of developmental disorders. Here we report biallelic mutations in the nucleoporin NUP88 as a novel cause of lethal fetal akinesia deformation sequence (FADS) in two families. FADS comprises a spectrum of clinically and genetically heterogeneous disorders with congenital malformations related to impaired fetal movement. We show that genetic disruption of nup88 in zebrafish results in pleiotropic developmental defects reminiscent of those seen in affected human fetuses, including locomotor defects as well as defects at neuromuscular junctions. Phenotypic alterations become visible at distinct developmental stages, both in affected human fetuses and in zebrafish, whereas early stages of development are apparently normal. The zebrafish phenotypes caused by nup88 deficiency are rescued by expressing wild-type Nup88 but not the disease-linked mutant forms of Nup88. Furthermore, using human and mouse cell lines as well as immunohistochemistry on fetal muscle tissue, we demonstrate that NUP88 depletion affects rapsyn, a key regulator of the muscle nicotinic acetylcholine receptor at the neuromuscular junction. Together, our studies provide the first characterization of NUP88 in vertebrate development, expand our understanding of the molecular events causing FADS, and suggest that variants in NUP88 should be investigated in cases of FADS.

Fetal movement is a prerequisite for normal fetal development and growth. Fetal akinesia deformation sequence (FADS) is the result of decreased fetal movement coinciding with congenital malformations related to impaired fetal movement. FADS may be caused by heterogenous defects at any point along the motor system pathway and genes encoding components critical to the neuromuscular junction and acetylcholine receptor clustering represent a major class of FADS disease genes. We report here biallelic, loss-of-function mutations in the nucleoporin NUP88 that result in lethal FADS and with this the first lethal human developmental disorder due to mutations in a nucleoporin gene. We show that loss of Nup88 in zebrafish results in defects reminiscent of those seen in affected human fetuses and loss of NUP88 affects distinct developmental stages, both during human and zebrafish development. Consistent with the notion that a primary cause for FADS is impaired formation of the neuromuscular junction, loss of Nup88 in zebrafish coincides with abnormalities in acetylcholine receptor clustering, suggesting that defective NUP88 function in FADS impairs neuromuscular junction formation.

Mechanical regulation of musculoskeletal system development

During embryogenesis, the musculoskeletal system develops while containing within itself a force generator in the form of the musculature. This generator becomes functional relatively early in development, exerting an increasing mechanical load on neighboring tissues as development proceeds. A growing body of evidence indicates that such mechanical forces can be translated into signals that combine with the genetic program of organogenesis. This unique situation presents both a major challenge and an opportunity to the other tissues of the musculoskeletal system, namely bones, joints, tendons, ligaments and the tissues connecting them. Here, we summarize the involvement of muscle-induced mechanical forces in the development of various vertebrate musculoskeletal components and their integration into one functional unit.

The Clinic Is My Laboratory: Life as a Clinical Geneticist

Clinical genetics is the application of advances in genetics and medicine to real human families. It involves diagnosis, care, and counseling concerning options available to affected individuals and their family members. Advances in medicine and genetics have led to dramatic changes in the scope and responsibilities of clinical genetics. This reflection on the last 50+ years of clinical genetics comes from personal experience, with an emphasis on the important contributions that clinical geneticists have made to the understanding of disease/disorder processes and mechanisms. The genetics clinic is a research laboratory where major advances in knowledge can and have been made.

Antenatal ultrasonography findings and magnetic resonance imaging in a case of Pena-Shokeir phenotype

Pena-Shokeir phenotype is a lethal anomaly characterized by neurogenic arthrogryposis, craniofacial anomalies, and pulmonary hypoplasia. This syndrome should be distinguished from trisomy 18 and arthrogryposis multiplex congenita for better counseling and establishing fetal prognosis. We present the case of a pregnant woman diagnosed with a Pena-Shokeir phenotype affected fetus at 24 weeks of gestation. Prenatal ultrasonography and fetal magnetic resonance imaging detected persistent hyperextension of the lumbar spine, micrognathia, absent septum pellucidum, and all characteristic features of Pena-Shokeir phenotype. Karyotyping was performed to exclude fetal chromosomal anomalies. Antenatal ultrasonography is an essential tool in the diagnosis of Pena-Shokeir phenotype while fetal magnetic resonance imaging is necessary to identify any associated anomalies of central nervous system.

Otopathologic Findings of Pena-Shokeir Syndrome Type I

BACKGROUND

Pena-Shokeir syndrome type I is a rare genetic disorder that includes multiple congenital facial and joint anomalies as well as pulmonary hypoplasia. Affected infants are usually premature, and 30% of them are stillborn. So far, studies have reported low-set ears in such infants, with no middle or inner ear findings.

METHOD

Histopathological study of human temporal bones with Pena-Shokeir syndrome type I.

RESULTS

Our case report describes an infant with severely decreased number of spiral ganglion cells and number of outer and inner hair cells of the cochlea, mild loss of vestibular hair cells, hypoplasia in the facial nerves, and ischemic degeneration of Schwann cells in the modiolus.

CONCLUSION

Pena-Shokeir syndrome type I is associated with a degenerative process in the labyrinth.

Next generation sequencing in a large cohort of patients presenting with neuromuscular disease before or at birth

BACKGROUND

Fetal akinesia/hypokinesia, arthrogryposis and severe congenital myopathies are heterogeneous conditions usually presenting before or at birth. Although numerous causative genes have been identified for each of these disease groups, in many cases a specific genetic diagnosis remains elusive. Due to the emergence of next generation sequencing, virtually the entire coding region of an individual's DNA can now be analysed through "whole" exome sequencing, enabling almost all known and novel disease genes to be investigated for disorders such as these.

METHODS

Genomic DNA samples from 45 patients with fetal akinesia/hypokinesia, arthrogryposis or severe congenital myopathies from 38 unrelated families were subjected to next generation sequencing. Clinical features and diagnoses for each patient were supplied by referring clinicians. Genomic DNA was used for either whole exome sequencing or a custom-designed neuromuscular sub-exomic supercapture array containing 277 genes responsible for various neuromuscular diseases. Candidate disease-causing variants were investigated and confirmed using Sanger sequencing. Some of the cases within this cohort study have been published previously as separate studies.

RESULTS

A conclusive genetic diagnosis was achieved for 18 of the 38 families. Within this cohort, mutations were found in eight previously known neuromuscular disease genes (CHRND, CHNRG, ECEL1, GBE1, MTM1, MYH3, NEB and RYR1) and four novel neuromuscular disease genes were identified and have been published as separate reports (GPR126, KLHL40, KLHL41 and SPEG). In addition, novel mutations were identified in CHRND, KLHL40, NEB and RYR1. Autosomal dominant, autosomal recessive, X-linked, and de novo modes of inheritance were observed.

CONCLUSIONS

By using next generation sequencing on a cohort of 38 unrelated families with fetal akinesia/hypokinesia, arthrogryposis, or severe congenital myopathy we therefore obtained a genetic diagnosis for 47% of families. This study highlights the power and capacity of next generation sequencing (i) to determine the aetiology of genetically heterogeneous neuromuscular diseases, (ii) to identify novel disease genes in small pedigrees or isolated cases and (iii) to refine the interplay between genetic diagnosis and clinical evaluation and management.

Muscle-bone interactions: basic and clinical aspects

Muscle and bone are anatomically and functionally closely connected. The traditional concept that skeletal muscles serve to load bone and transform skeletal segments into a system of levers has been further refined into the mechanostat theory, according to which striated muscle is essential for bone development and maintenance, modelling and remodelling. Besides biomechanical function, skeletal muscle and bone are endocrine organs able to secrete factors capable of modulating biological function within their microenvironment, in nearby tissues or in distant organs. The endocrine properties of muscle and bone may serve to sense and transduce biomechanical signals such as loading, unloading or exercise, or systemic hormonal stimuli into biochemical signals. Nonetheless, given the close anatomical relationship between skeletal muscle and bone, paracrine interactions particularly at the periosteal interface can be hypothesized. These mechanisms can assume particular importance during bone and muscle healing after musculoskeletal injury. Basic studies in vitro and in rodents have helped to dissect the multiple influences of skeletal muscle on bone and/or expression of inside-organ metabolism and have served to explain clinical observations linking muscle-to-bone quality. Recent evidences pinpoint that also bone tissue is able to modulate directly or indirectly skeletal muscle metabolism, thus empowering the crosstalk hypothesis to be further tested in humans in vivo.

Arthrogryposis and fetal hypomobility syndrome

Arthrogryposis is a heterogeneous condition, evident from birth, which can be defined as multiple contractures of the joints. The etiology is multifold: genetic disorders of the central or peripheral nervous system, or of the connective tissue leading to decreased fetal movements, and vascular and environmental causes. The problem begins in utero. There may be overlapping conditions between sporadic, syndromic, neurogenic, myopathic and metabolic types. The workup should include a family tree. Systemic involvement, for example of the renal and pulmonary systems, may be encountered in associated syndromes. Motor neuron disorders leading to the condition are the most commonly seen type. Fetal or neonatal akinesia/hypokinesia is at the severe end of the spectrum, in which there is literally intrauterine limitation of movement. Children with amyplasia are born with little or diminished muscle bulk of the extremities. Distal arthrogryposis is almost always a dominantly inherited condition. A multidisciplinary care approach is required in order to provide optimum healthcare. The management team should include a nutritionist and a physiotherapist. Genetic counseling is possible in most instances. A truly genetic cause can be identified in more than 50% of cases. Survivors, though handicapped, can lead near normal lives.

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.

Anesthetic management of three pediatric cases with Pena-Shokeir syndrome

Pena-Shokeir syndrome is a rare, early lethal disease. It is characterized by fetal growth restriction; craniofacial deformities, for example micrognathia and microcephaly; multiple ankyloses; and pulmonary hypoplasia. For patients with this syndrome, maintenance of airway and control of perioperative respiratory complications are important for anesthetic management. We report 3 pediatric cases of Pena-Shokeir syndrome undergoing tracheostomy and arthrolysis under general anesthesia using sevoflurane, nitrous oxide, fentanyl, and vecuronium bromide. Anesthetic procedures including mask ventilation, tracheal intubation, and extubation were successfully performed without complications during and after surgery. In patients with Pena-Shokeir syndrome, inhalational anesthetics can be safely used for induction and maintenance of anesthesia, although it is important to assume that difficult airway management might be encountered.

Biophysical stimuli induced by passive movements compensate for lack of skeletal muscle during embryonic skeletogenesis

In genetically modified mice with abnormal skeletal muscle development, bones and joints are differentially affected by the lack of skeletal muscle. We hypothesise that unequal levels of biophysical stimuli in the developing humerus and femur can explain the differential effects on these rudiments when muscle is absent. We find that the expression patterns of four mechanosensitive genes important for endochondral ossification are differentially affected in muscleless limb mutants, with more extreme changes in the expression in the humerus than in the femur. Using finite element analysis, we show that the biophysical stimuli induced by muscle forces are similar in the humerus and femur, implying that the removal of muscle contractile forces should, in theory, affect the rudiments equally. However, simulations in which a displacement was applied to the end of the limb, such as could be caused in muscleless mice by movements of the mother or normal littermates, predicted higher biophysical stimuli in the femur than in the humerus. Stimuli induced by limb movement were much higher than those induced by the direct application of muscle forces, and we propose that movements of limbs caused by muscle contractions, rather than the direct application of muscle forces, provide the main mechanical stimuli for normal skeletal development. In muscleless mice, passive movement induces unequal biophysical stimuli in the humerus and femur, providing an explanation for the differential effects seen in these mice. The significance of these results is that forces originating external to the embryo may contribute to the initiation and progression of skeletal development when muscle development is abnormal.

Mechanical influences on morphogenesis of the knee joint revealed through morphological, molecular and computational analysis of immobilised embryos

Very little is known about the regulation of morphogenesis in synovial joints. Mechanical forces generated from muscle contractions are required for normal development of several aspects of normal skeletogenesis. Here we show that biophysical stimuli generated by muscle contractions impact multiple events during chick knee joint morphogenesis influencing differential growth of the skeletal rudiment epiphyses and patterning of the emerging tissues in the joint interzone. Immobilisation of chick embryos was achieved through treatment with the neuromuscular blocking agent Decamethonium Bromide. The effects on development of the knee joint were examined using a combination of computational modelling to predict alterations in biophysical stimuli, detailed morphometric analysis of 3D digital representations, cell proliferation assays and in situ hybridisation to examine the expression of a selected panel of genes known to regulate joint development. This work revealed the precise changes to shape, particularly in the distal femur, that occur in an altered mechanical environment, corresponding to predicted changes in the spatial and dynamic patterns of mechanical stimuli and region specific changes in cell proliferation rates. In addition, we show altered patterning of the emerging tissues of the joint interzone with the loss of clearly defined and organised cell territories revealed by loss of characteristic interzone gene expression and abnormal expression of cartilage markers. This work shows that local dynamic patterns of biophysical stimuli generated from muscle contractions in the embryo act as a source of positional information guiding patterning and morphogenesis of the developing knee joint.

Inherited neuroaxonal dystrophy in dogs causing lethal, fetal-onset motor system dysfunction and cerebellar hypoplasia

Neuroaxonal dystrophy in brainstem, spinal cord tracts, and spinal nerves accompanied by cerebellar hypoplasia was observed in a colony of laboratory dogs. Fetal akinesia was documented by ultrasonographic examination. At birth, affected puppies exhibited stereotypical positioning of limbs, scoliosis, arthrogryposis, pulmonary hypoplasia, and respiratory failure. Regional hypoplasia in the central nervous system was apparent grossly, most strikingly as underdeveloped cerebellum and spinal cord. Histopathologic abnormalities included swollen axons and spheroids in brainstem and spinal cord tracts; reduced cerebellar foliation, patchy loss of Purkinje cells, multifocal thinning of the external granular cell layer, and loss of neurons in the deep cerebellar nuclei; spheroids and loss of myelinated axons in spinal roots and peripheral nerves; increased myocyte apoptosis in skeletal muscle; and fibrofatty connective tissue proliferation around joints. Breeding studies demonstrated that the canine disorder is a fully penetrant, simple autosomal recessive trait. The disorder demonstrated a type and distribution of lesions homologous to that of human infantile neuroaxonal dystrophy (INAD), most commonly caused by mutations of phospholipase A2 group VI gene (PLA2G6), but alleles of informative markers flanking the canine PLA2G6 locus did not associate with the canine disorder. Thus, fetal-onset neuroaxonal dystrophy in dogs, a species with well-developed genome mapping resources, provides a unique opportunity for additional disease gene discovery and understanding of this pathology.

Mechanobiology of embryonic skeletal development: Insights from animal models

A range of clinical conditions in which fetal movement is reduced or prevented can have a severe effect on skeletal development. Animal models have been instrumental to our understanding of the interplay between mechanical forces and skeletal development, particularly the mouse and the chick model systems. In the chick, the most commonly used means of altering the mechanical environment is by pharmaceutical agents which induce paralysis, whereas genetically modified mice with nonfunctional or absent skeletal muscle offer a valuable tool for examining the interplay between muscle forces and skeletogenesis in mammals. This article reviews the body of research on animal models of bone or joint formation in vivo in the presence of an altered or abnormal mechanical environment. In both immobilized chicks and "muscleless limb" mice, a range of effects are seen, such as shorter rudiments with less bone formation, changes in rudiment and joint shape, and abnormal joint cavitation. However, although all bones and synovial joints are affected in immobilized chicks, some rudiments and joints are unaffected in muscleless mice. We propose that extrinsic mechanical forces from movements of the mother or littermates impact on skeletogenesis in mammals, whereas the chick embryo is reliant on intrinsic movement for mechanical stimulation. The insights gained from animal models into the mechanobiology of embryonic skeletal development could provide valuable cues to prospective tissue engineers of cartilage and bone and contribute to new or improved treatments to minimize the impact on skeletal development of reduced movement in utero.

Fetal akinesia deformation sequence with delayed skeletal muscle maturation and polymicrogyria: evidence for a hypoxic/ischemic pathogenesis

Multiple congenital contractures, also known as fetal akinesia deformation sequence (FADS) and related terms, result from decreased fetal movement. The underlying etiologies are diverse and include central nervous system (CNS) dysgeneses and primary myopathies. Persistent central nuclei or the presence of myotubes is often regarded as evidence of a primary myopathic etiology; however, these findings are also associated with impaired fetal innervation. We report 7 fetuses, estimated gestational age 20 to 23 weeks, with persistent myotubular morphology, a change that could be (mis)interpreted as a primary myopathy. In 4 of the patients, CNS histology showed hypoxic/ischemic injury, polymicrogyria, mineralized neurons, and microinfarcts with or without loss of anterior horn neurons. FADS cases with polymicrogyria have frequently been interpreted as a consequence of a primary brain malformation. Only a few descriptions of FADS associate polymicrogyria with CNS hypoxic/ischemic injury, however, and do not describe skeletal muscle maturation delay. We hypothesize that this combination of neural and muscular pathology is an under-recognized pattern in FADS, which results from diffuse hypoxic/ischemic injury involving the brain and spinal cord during early to middle gestation.

Serial postural and motor assessment of Fetal Akinesia Deformation Sequence (FADS)

BACKGROUND

Fetal Akinesia Deformation Sequence (FADS) is a rare, in most cases autosomal recessive, disorder. Its heterogeneous origin results in variable onset and expression of motor and postural anomalies. DNA-diagnostic possibilities are limited, thus prenatal diagnosis is chiefly dependent on sonographic examinations.

AIM

To explore postural and motor development from a systematic sonographic protocol for fetuses at high risk for FADS. Specific questions are: which motor (i.e., specific movement patterns, quality and quantity of general movements) and postural aspects are most informative about emerging FADS and is the gestational age of onset range of FADS more limited for siblings?

METHODS

Ten families underwent 45, 15-minute sonographic assessments for motility and posture for ten index fetuses with FADS and nine subsequent pregnancies from five families.

RESULTS

FADS was diagnosed between 18 and 33 weeks gestation in ten index pregnancies and between 11 and 18 weeks gestation in 4/9 subsequent pregnancies, 1-12 weeks earlier than their index pregnancies. From the four assessment aspects, posture and movement quality were always abnormal, movement quantity in 7/14 and differentiation into specific movement patterns were reduced in comparison with healthy siblings (p<0.01). Deterioration occurred in a 2 week period.

CONCLUSIONS

Serial postural and qualitative assessments were most informative diagnosing FADS. Quantity and differentiation into specific movement patterns contributed substantially. Onset range of FADS within siblings was suggested to be more limited than between families.

Pena-Shokeir phenotype (fetal akinesia deformation sequence) revisited

BACKGROUND

Pena and Shokeir described the phenotype of two sisters in 1974, and subsequently their features have become recognized as a sequence of deformational changes related to decreased or absent fetal movement (fetal akinesia deformation sequence [FADS]), because of the work of Moessinger (1983).

METHODS

Identification of reported cases by searching Online Mendelian Inheritance in Man, Medlines, the London Dysmorphology Database, and the references found in these articles. These case reports were reviewed, tabulated, and summarized.

RESULTS

It is now possible to recognize at least 20 familial types of Pena-Shokeir phenotype (PSP), based on the differences found in the reports of the natural history and pathology found at fetal and newborn autopsy. In addition, characteristic changes in the central nervous system seen with embryonic/fetal vascular compromise have been recognized in many reported cases. Most of the reported cases of PSP/FADS related to vascular compromise are sporadic, but familial cases have also been reported.

CONCLUSION

Lack of fetal movement (fetal akinesia) in humans produces a recognizable sequence of deformations. Many developmental processes must be accomplished for fetal movement to be normal, and for extra-uterine life to be sustainable. Prenatal diagnosis is possible through real-time ultrasound studies as early as 12 weeks. Most reported cases die in utero, at birth, or in the newborn period. Advances in embryo/fetus pathology have led to the recognition of the many familial subtypes, allowing improved genetic counseling and early recognition in subsequent pregnancies.

Muscle contraction is necessary to maintain joint progenitor cell fate

During embryogenesis, organ development is dependent upon maintaining appropriate progenitor cell commitment. Synovial joints develop from a pool of progenitor cells that differentiate into various cell types constituting the mature joint. The involvement of the musculature in joint formation has long been recognized. However, the mechanism by which the musculature regulates joint formation has remained elusive. In this study, we demonstrate, utilizing various murine models devoid of limb musculature or its contraction, that the contracting musculature is fundamental in maintaining joint progenitors committed to their fate, a requirement for correct joint cavitation and morphogenesis. Furthermore, contraction-dependent activation of beta-catenin, a key modulator of joint formation, provides a molecular mechanism for this regulation. In conclusion, our findings provide the missing link between progenitor cell fate determination and embryonic movement, two processes shown to be essential for correct organogenesis.

The influence of prenatal breech presentation on neonatal leg posture

The aim of our study was to examine the effect of prenatal breech presentation on postnatal leg posture. Twelve infants were born after breech presentation and nine infants after cephalic presentation participated. At 2, 4, 6, 12 and 18 weeks postnatal age leg posture was examined during general movements in supine and vertical position.

RESULTS

Transient differences in hip posture between the groups were observed during the first 6 weeks postnatal age, with significantly more hip flexion and less hip extension in the breech group. For knee extension, differences between the groups were not statistically significant. Changing from supine to vertical position, the breech group demonstrated a significant increase in hip extension, with no significant changes in hip posture for the cephalic group. For both groups the vertical condition resulted in a significant increase in knee extension. Continuity from pre- to postnatal life was found for hip posture in both groups and for knee extension only in the breech group.

CONCLUSIONS

Significant differences between breech and cephalic-born infants were found during the first 6 weeks after birth and mainly concerned hip posture and not knee posture. An increase in gravitational force has more impact on leg posture in the breech than in the cephalic group. The observed differences in hip posture between the studied groups were found to be transient, however, in the long term subtle differences still remain between the groups.

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.

Genetics of arthrogryposis: linkage analysis approach

Arthrogryposis multiplex congenita (AMC) is a heterogeneous group of congenital contracture syndromes, some of which are hereditary. To date, four genetic loci associated with autosomal recessive arthrogryposis syndromes have been identified using the powerful tools of genome-wide linkage analysis and homozygosity mapping. In the consanguineous inbred Bedouin population in southern Israel there is an unusually high incidence of hereditary arthrogryposis. We hypothesized the high incidence of this phenotype in this specific cohort might be due to a founder effect: a mutation that occurred several generations ago, spread throughout various tribes in that population in recent generations and causes the phenotype in its homozygous form. Using linkage analysis studies, we showed the hereditary arthrogryposis in those tribes does not stem from a single genetic defect. Thus, there is genetic heterogeneity of congenital arthrogryposis in this population: the same phenotype is caused by mutations in different genes, yet to be unraveled.

Early fetal akinesia deformation sequence: a case report with unusual autoptic features

In this paper we report a case of early onset fetal akinesia, with unusual pathological findings. This is a product of medical abortion of young, healthy, unrelated parents. The mother's obstetrical history revealed two previous early miscarriages and a suspicion of FADS in the second previous gestation. At 17 weeks of gestation, an ultrasound examination disclosed absence of fetal movements, fixed extended knees and deformation of the feet. Amniocentesis showed a normal 46, XX karyotype. Hydrops fetalis and multiple skin webs (pterygia), which are usually present in cases of early fetal akinesia, were absent. A diagnosis of arthrogryposis was made and the pregnancy was terminated at 17 weeks of gestation. Postmortem examination was performed according to the necropsy technique suggested by Langley. Thus, body weight and external measurement, including crown-rump, crown-heel, foot lengths, head, thorax and abdominal circumferences were estimated and compared with standard values for assessment of fetal growth. External dysmorphic features were evaluated prior to the evisceration. On internal examination the location and shape of every organ was evaluated. Every organ, skin, muscles from different parts of the body, the brain and spinal cord were sampled and histologically examined. External examination revealed a female fetus with marked muscular hypoplasia of upper and lower extremities with thin arms and legs and multiple joint contractures of lower extremities. The face showed a flattened nose, micrognatia, hypertelorism, cleft palate and low-set ears. There was also a small nuchal fold. The abdomen was distended with a very thin and almost transparent wall. Histologically, muscles were characterized by severe fibrosis with fatty infiltration and by moderate variability in diameter of muscle fibers. The spinal cord disclosed a paucity of anterior horn motor neurons. We suggest multiple pterygium as a diagnosis. Lethal multiple pterygium syndrome (LMPS) is only a symptom and the precise diagnosis is more likely to be spinal atrophy. We, moreover believe that the paucity of spinal motoneurons could be due to the anomalies of programmed death during fetal development and the consequence of genetic defects.

Three cases with de novo 6q imbalance and variable prenatal phenotype

We describe two families in which three fetuses had a de novo 6q imbalance and abnormal phenotypes. We determined the boundaries and the parental origin of the chromosomal alterations by segregation analysis using a panel of short tandem repeats (STRs) located on 6q. Cases 1 and 2 (family A) were two sibs with 6q imbalance involving different regions. Case 1 was a female fetus with arthrogryposis, who had a complex rearrangement resulting in two deleted regions (6q22 and 6q25.1-q25.2) and a duplication of 6q23-q25.1. This latter imbalance was reported previously and is associated with joint contractures and short neck, also present in this fetus. The sib (case 2) had intrauterine growth restriction (IUGR) and agenesis of the ductus venosus. This male died shortly after birth; postnatal karyotype and molecular investigations showed a 6q21 de novo deletion. Case 3 (family B) had a prenatally detected deletion of 6q14-q16. Autopsy of the fetus documented minor facial anomalies and contractures of the limbs. All rearrangements were de novo and of paternal origin. Our data and the consistent number of cases of de novo 6q alterations previously reported suggest that chromosome arm 6q could be prone to rearrangements resulting in heterogeneous phenotypes. In family A, chromosome 6q imbalances involving different chromosomal regions were present in two consecutive pregnancies. In such cases counseling should suggest the impossibility of excluding recurrence of a chromosomal imbalance, and should discuss the option of early prenatal diagnosis in subsequent pregnancies.

Acute Respiratory Distress in Pena-Shokeir Syndrome

Pena-Shokeir syndrome is a rare, autosomal-recessive disorder that usually affects newborns. Its etiology is poorly understood. Pena-Shokeir syndrome is defined by camptodactyly, multiple ankyloses, pulmonary hypoplasia, and various facial anomalies. These manifestations are usually severe, and death generally occurs at birth or shortly thereafter. We describe a case of Pena-Shokeir syndrome in a 9-year-old girl of above-normal intelligence who presented with life-threatening airway distress. To the best of our knowledge, she is the oldest living individual with Pena-Shokeir syndrome, and the only such patient whose intelligence was not impaired. We discuss the acute management and subsequent care of this patient, who not only survived, but maintained excellent grades in school.

Expression of angiogenesis-related factors in lungs of patients with congenital diaphragmatic hernia and pulmonary hypoplasia of other causes

Congenital diaphragmatic hernia (CDH) is a congenital disorder, complicated by pulmonary hypoplasia (PH) and pulmonary hypertension. Hypoplastic lungs have fewer and smaller airspaces than normal, with thicker interalveolar septa; the adventitia and media of pulmonary arteries are thickened, and the total size of the pulmonary vascular bed is decreased compared to normal. Although histological abnormalities in PH have been described, less is known about the underlying molecular mechanisms. Therefore, we have investigated a series of proteins, known to be involved in angiogenesis, including von Hippel-Lindau protein (pVHL), hypoxia-inducible factor-1a (HIF-1a), vascular endothelial growth factor (VEGF), fetal liver kinase 1 (Flk-1), and endothelial and inducible nitric oxide synthase (eNOS, iNOS) by immunohistochemistry on paraffin-embedded lung tissue of CDH patients ( n = 13), patients with lung hypoplasia due to other causes ( n = 20), and normal controls ( n = 33). pVHL was expressed more frequently in the arterial smooth muscle cells of CDH lungs compared with both other groups. Furthermore, HIF-1a was expressed less frequently in the endothelium of arteries, veins, and capillaries of CDH lungs as compared with both other groups. No differences were observed in the expression patterns of VEGF, Flk-1, eNOS, and iNOS between the different groups. Our data suggest a role for pVHL and HIF-1a in normal and abnormal pulmonary angiogenesis. The differential expression of these proteins may provide a molecular basis for the histological differences observed in the lung vessels of patients with CDH.

Obstetric aspects of the Prader-Willi syndrome

The Prader-Willi syndrome (PWS) is a complex, multisystem disorder. The syndrome affects the central nervous system, with a predilection for the hypothalamus. The clinical picture in PWS is very variable, and depends on the age of the affected child. Frequently, the most prominent features such as obesity, mental retardation and behavioral disorders do not become evident until the later childhood stage, which can lead to underdiagnosis or late diagnosis in early childhood. Because of the long-term implications of this syndrome, it is important to recognize its features as soon as possible so that early counseling of parents and the affected child is possible. Because PWS can also lead to complications in both pregnancy and labor, proper diagnosis in the fetus can also help optimize perinatal care in affected children. In three cases we illustrate that certain combinations of obstetric symptoms such as polyhydramnios, diminished fetal movements, malpresentation and abnormal fetal heart rhythm can help alert clinicians to the possibility of this syndrome in fetuses.

A new autosomal recessive congenital contractural syndrome in an Israeli Bedouin kindred

We describe 23 cases with a syndrome of congenital contractures belonging to a large, inbred Israeli-Bedouin kindred. The phenotype described is similar to the Finnish type lethal congenital contracture syndrome yet differs in the following ways: by some additional craniofacial/ocular findings, by the lack of hydrops, multiple pterygia, and fractures, and by the normal duration of pregnancy. The major unique and previously undescribed clinical feature in our patients is a markedly distended urinary bladder as well as other urinary abnormalities. The vast majority of the cases died shortly after birth. Sonographic prenatal diagnosis was possible as early as 15 weeks gestation by demonstrating fetal akinesia, limb contractures, hydramnios, and distended urinary bladder. Linkage to 5q and 9q34 loci has been excluded.

Fetal akinesia deformation sequence: a study of 30 consecutive in utero diagnoses

The etiology of the fetal akinesia deformation sequence (FADS) is heterogeneous and can be the result of neurogenic and myopathic disorders, restrictive dermopathy, teratogen exposure, and intrauterine constraint. We present the prenatal and fetopathological findings in a consecutive series of 30 affected fetuses with normal chromosomal results. According to the in utero time of onset of the fetal akinesia, the severity of the phenotype varied from a severe, generalized FADS in the early-onset group to milder defects, as isolated distal arthrogryposis in the late-onset group. No more than 10% (3/30) were diagnosed in the first trimester of pregnancy and all presented a severe phenotype. Twenty-seven of the thirty (90%) were diagnosed after the first trimester, with a severe FADS in 15/27 and a milder phenotype of distal arthrogryposis in 12/27. In all 30 patients, extensive neuropathological studies (brain, spinal cord, and muscles) were performed. In 16 patients (53%) a specific diagnosis could be made (central nervous system abnormalities 9/16; spinal cord 1/16; primary myopathy 3/16; syndromic 3/16). In 10 others (33%), pathological neuromuscular findings were present but no definitive diagnosis was established. In 4 patients (13%), neuromuscular findings were normal, and the etiology of the FADS remained unexplained.