Fetal Akinesia Syndrome Research Articles

CONGENITAL MYOPATHIES – NEMALINE MYOPATHIES: EP.37 ACTA1 congenital myopathy: clinical and genetic spectrum of 5 chilean newborns

Congenital myopathy related with ACTA1 mutation may produce very severe and less severe clinical pictures with different genetic and histopathologic features. We describe clinical and histopathologic features of 5 newborns (two girls) studied between 2013 and 2020 in Clinica Alemana de Santiago and Hospital Luis Calvo Mackenna. Genetic analysis was performed in Hospital Bambino Gesú and Invitae (commercial laboratory USA). The first patient studied (2013) was a girl with fetal akinesia syndrome. She was ventilator dependent since birth, had no movements and presented distal contractures. Histopathology showed myopathic unspecific findings. She died at 6 months of age. Genetic study showed an ACTA 1 de novo mutation. Patients 2 and 3 are boys with neonatal hypotonia, weakness, facial diplegia and mild transient respiratory problems. Patients 2 and 3 had muscle biopsy with cytoplasmic rods. Both showed progressive motor improvement. Genetic analysis showed ACTA1 mutation de novo (patient 2) and autosomal recessive (patient 3). Patient 4 was a girl who showed severe generalized muscular weakness, facial diplegia, ventilatory dependence and progressive dilated myocardiopathy. Muscle biopsy showed type 1 fiber atrophy. Genetic study showed ACTA 1 de novo mutation. She died at 5 months of age. Patient 5, a 1-year-old boy with severe hypotonia and weakness, facial diplegia eyelid ptosis and mechanical ventilator dependent since birth. Muscle biopsy showed unspecific myopathic findings and genetic study detected ACTA 1 de novo mutation. We conclude that de novo ACTA1 mutation correlates with more severe and even fatal outcome (3 out of 4 of our patients) and AR ACTA1 mutation correlates with a more benign outcome (1 of our patients). Finally, muscle histopathology with rods seems to predict a less severe outcome but this is too small a series to validate this hypothesis.

Genetic diagnosis and clinical evaluation of severe fetal akinesia syndrome.

ObjectiveIn this retrospective study, we describe the clinical course, ultrasound findings and genetic investigations of fetuses affected by fetal akinesia.Materials and MethodsWe enrolled 22 eukaryotic fetuses of 18 families, diagnosed with fetal akinesia between 2008 and 2016 at the Department of Obstetrics and Feto‐Maternal Medicine at the Medical University of Vienna. Routine genetic evaluation included karyotyping and chromosomal microarray analysis. Retrospectively, exome sequencing was performed in the index case of 11 families, if stored DNA was available. Confirmation analyses and genetic diagnosis of siblings were performed by using Sanger sequencing.ResultsWhole exome sequencing identified pathogenic variants of CNTN1, RYR1, NEB, GLDN, HRAS and TNNT3 in six cases of 11 families. In three of these families, the variants were confirmed in the respective sibling.ConclusionsThe present study demonstrates a high diagnostic yield of exome sequencing in fetuses affected by akinesia syndrome, especially if family history is positive. Still, in a large part the underlying genetic cause remained unknown, whereas precise clinical evaluation in combination with exome sequencing shows to be the best tool to find the disease causing variants.

Clinical and laboratory diagnosis of congenital Zika virus syndrome and diaphragmatic unilateral palsy: case report

Abstract Introduction: several birth defects associated to congenital Zika virus infection have been reported, although the clinical features have not been fully characterized. Description: this is the first case report on unilateral diaphragmatic paralysis diagnosed on a neonate with congenital Zika confirmed by the examination of the amniotic fluid through polymerase chain reaction (ZIKV RT-PCR) and the examination of cerebrospinal fluid by serological test (IgM ZIKV-ELISA) after birth. The main manifestations detected by intrauterine ultrasound were: microcephaly, ventriculomegaly, intracranial calcifications, enlarged cisterna magna, increased amniotic fluid index and fetal akinesia syndrome. The newborn had acute respiratory failure in the first hours of life, requiring mechanical ventila-tion. The X- ray of the chest showed unilateral diaphragmatic paralysis and cardiomegaly. Discussion: diaphragmatic palsy in congenital Zika has not been previously reported, the etiopathogenic mechanisms of this event in congenital Zika virus needs to be elucidated.

An exome sequencing strategy to diagnose lethal autosomal recessive disorders

Rare disorders resulting in prenatal or neonatal death are genetically heterogeneous. For some conditions, affected fetuses can be diagnosed by ultrasound scan, but this is not usually possible until mid-gestation. There is often limited fetal DNA available for investigation. We investigated a strategy for diagnosing autosomal recessive lethal disorders in non-consanguineous pedigrees with multiple affected fetuses. Exome sequencing was performed to identify genes where each parent is heterozygous for a rare non-synonymous-coding or splicing variant. Putative pathogenic variants were tested for cosegregation in affected fetuses and unaffected siblings. In eight couples of European ancestry, we found on average 1.75 genes (range 0–4) where both parents were heterozygous for rare potentially deleterious variants. A proof-of-principle study detected heterozygous DYNC2H1 variants in a couple whose five fetuses had short-rib polydactyly. Prospective analysis of two couples with multiple pregnancy terminations for fetal akinesia syndrome was performed and a diagnosis was obtained in both the families. The first couple were each heterozygous for a previously reported GLE1 variant, p.Arg569His or p.Val617Met; both were inherited by their two affected fetuses. The second couple were each heterozygous for a novel RYR1 variant, c.14130-2A>G or p.Ser3074Phe; both were inherited by their three affected fetuses but not by their unaffected child. Biallelic GLE1 and RYR1 disease-causing variants have been described in other cases with fetal akinesia syndrome. We conclude that exome sequencing of parental samples can be an effective tool for diagnosing lethal recessive disorders in outbred couples. This permits early prenatal diagnosis in future pregnancies.

Postnatally Diagnosed Agenesis of Corpus Callosum in Fetuses

Objectives: To examine and characterize the agenesis of the corpus calosum (ACC) in an epidemiological study of fetal autopsies, as well as, to analyze the associated anomalies and to emphasize the importance of the clinical examination of ACC. Methods: The subjects of observation are 20 fetuses from a total of 2238 autopsies carried out during a period of three years (2006–2009) in Tunis. Results: The associated abnormalities are hydrocephalus, cerebellar hypoplasia, agenesis of vermis cerebelli, polymicrogyria and lissencephaly. Sixteen of the cases (80%) are syndromic: Trisomy 13,18,21 (5,1,2 fetuses respectively) and Thanatophoric dysplasia, Fetal akinesia syndrome, Dandy-Walker Malformation and the Association VACTERL are represented by two cases each. Conclusion: The prenatal diagnosis of ACC must be the result of a multidisciplinary approach. The phenotype of the XLAG syndrome creates an interest to study asymptomatic patients with ACC, especially when the anomaly is detected prenatally.

Fetal akinesia in metatropic dysplasia: The combined phenotype of chondrodysplasia and neuropathy?

Dominant mutations in the receptor calcium channel gene TRPV4 have been associated with a family of skeletal dysplasias (metatropic dysplasia, pseudo-Morquio type 2, spondylometaphyseal dysplasia, Kozlowski type, brachyolmia, and familial digital arthropathy) as well as with dominantly inherited neuropathies (hereditary motor and sensory neuropathy 2C, scapuloperoneal spinal muscular atrophy, and congenital distal spinal muscular atrophy). While there is phenotypic overlap between the various members of each group, the two groups were considered to be totally separate with the former being strictly a structural skeletal condition and the latter group being confined to the peripheral nervous system. We report here on fetal akinesia as the presenting feature of severe metatropic dysplasia, suggesting that certain TRPV4 mutations can cause both a skeletal and a neuropathic phenotype. Three cases were detected on prenatal ultrasound because of absent movements in the second trimester. Case 4 presented with multiple joint contractures and absent limb movements at birth and was diagnosed with "fetal akinesia syndrome". Post-interruption and post-natal X-rays showed typical features of metatropic dysplasia in all four. Sequencing of the TRPV4 gene confirmed the presence of de novo heterozygous mutations predicting G78W (Case 1), T740I (Cases 2 and 3), and K276E (Case 4). Although some degree of restriction of movements is not uncommon in fetuses with skeletal dysplasia, akinesia as leading sign is unusual and suggests that certain TRPV4 mutations produce both chondrodysplasia and a peripheral neuropathy resulting in a severe "overlap" phenotype.

Dominant and recessive central core disease associated with RYR1 mutations and fetal akinesia

We studied seven patients (fetuses/infants) from six unrelated families affected by central core disease (CCD) and presenting with a fetal akinesia syndrome. Two fetuses died before birth (at 31 and 32 weeks) and five infants presented severe symptoms at birth (multiple arthrogryposis, congenital dislocation of the hips, severe hypotonia and hypotrophy, skeletal and feet deformities, kyphoscoliosis, etc.). Histochemical and ultrastructural studies of muscle biopsies confirmed the diagnosis of CCD showing unique large eccentric cores. Molecular genetic investigations led to the identification of mutations in the ryanodine receptor (RYR1) gene in three families, two with autosomal recessive (AR) and one with autosomal dominant (AD) inheritance. RYR1 gene mutations were located in the C-terminal domain in two families (AR and AD) and in the N-terminal domain of the third one (AR). This is the first report of mutations in the RYR1 gene involved in a severe form of CCD presenting as a fetal akinesia syndrome with AD and AR inheritances.

Alpers progressive infantile neuronal poliodystrophy: an acute neonatal form with findings of the fetal akinesia syndrome.

We report on 8 patients from two families with Alpers syndrome. The onset in one family was prenatal and in the 4 patients who were examined, severe microcephaly, intrauterine growth retardation, and typical manifestations of fetal akinesia, including retrognathia, joint limitations, and chest deformity were found. The second family presented with an early infantile form. All the affected offspring had micrognathia and one had findings of fetal akinesia, comparable to those seen in the other family. Microcephaly was mild at birth and progressed with age. Refractory neonatal convulsions, swallowing difficulties, and pneumonia complicated the clinical course of patients in both families, and all the patients died before age 20 months. Results of comprehensive biochemical and metabolic studies in both families were normal and the diagnosis was supported by demonstration of extensive progressive brain atrophy on CT and typical histological findings. Patients without a detectable defect in energy metabolism and normal liver histology comprise a distinct subset of Alpers syndrome. Until the metabolic defect(s) is defined, we suggest naming the acute neonatal form of this subset of Alpers syndrome "type 1."

Two Cases of Fetal Akinesia/Hypokinesia Sequence

Two cases of fetal akinesia sequence are described. Both showed facial anomalies, arthrogryposis multiplex, bilateral camptodactyly, and pulmonary hypoplasia. One child had degeneration of large motor neurons of the thoracolumbosacral spinal cord and irregular atrophy of diaphragm; the other had left microphthalmia, hemiatrophy of the left temporal lobe with calcification of degenerated neurons, and hypoplasia of the cervothoracic spinal cord with decrease and degeneration of neurons. The iliopsoas and intercostal muscles showed focal myofiber atrophy. These findings suggested that some instances of this fetal akinesia syndrome might be due to neuromuscular dysfunction that occurred in utero and may have various causes.