Possible incomplete penetrance of Xq28 int22h-1/int22h-2 duplication

Xq28 int22h-1/int22h-2 duplication is the result of non-allelic homologous recombination between int22h-1/int22h-2 repeats separated by 0.5 Mb. It is responsible for a syndromic form of intellectual disability (ID), with recurrent infections and atopic diseases. Minor defects, nonspecific facial dysmorphic features, and overweight have also been described. Half of female carriers have been reported with ID, whereas all reported evaluated born males present mild to moderate ID, suggesting complete penetrance. We collected data on 15 families from eight university hospitals. Among them, 40 patients, 21 females (one fetus), and 19 males (two fetuses), were carriers of typical or atypical Xq28 int22h-1/int22h-2 duplication. Twenty-one individuals were considered asymptomatic (16 females and 5 males), without significantly higher rate of recurrent infections, atopia, overweight, or facial dysmorphism. Approximately 67% live-born males and 23% live-born female carriers of the typical duplication did not have obvious signs of intellectual disability, suggesting previously undescribed incomplete penetrance or low expression in certain carriers. The possibility of a second-hit or modifying factors to this possible susceptibility locus is yet to be studied but a possible observational bias should be considered in assessing such challenging X-chromosome copy number gains. Additional segregation studies should help to quantify this newly described incomplete penetrance.

The Largest Germline Heterozygous Deletion Encompassing Potocki-Shaffer and WAGR Syndromes Loci to Date: A Case Report

Potocki-Schaffer syndrome includes multiple exostoses, parietal foramina, and variable developmental delay/intellectual disability. It is associated with a heterozygous deletion of the 11p12p11.2 region. In some cases, the deletion extends to the WAGR locus (11p13p12). We describe here a 9-month-old girl harboring the largest germline heterozygous deletion characterized so far. Oligohydramnios and parietal foramina were noticed during pregnancy. No patient has been diagnosed before with concomitance of these two syndromes during the prenatal period. Cytogenetic diagnosis was anticipated on basis of clinical and radiological signs. Postnatal conventional karyotype confirmed an interstitial 11p deletion: 46,XX,del(11)(p11.2p15.1). Array-comparative genomic hybridization characterized a 29.6 Mb deletion. Our case illustrates the interest of high-resolution genomic approaches to correlate adequately clinical phenotypes with specific genes in suspected contiguous gene deletion syndromes.

The GRIA3 c.2477G > A Variant Causes an Exaggerated Startle Reflex, Chorea, and Multifocal Myoclonus

BACKGROUND

Hemizygous mutations in GRIA3 encoding the GluA3 subunit of the amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor are known to be associated with neurodevelopmental disorders, including intellectual disability, hypotonia, an autism spectrum disorder, sleep disturbances, and epilepsy in males.

OBJECTIVE

To describe a new and consistent phenotype in 4 affected male patients associated with an undescribed deleterious variant in GRIA3.

METHODS

We evaluated a large French family in which segregate a singular phenotype according to an apparent X-linked mode of inheritance. Molecular analyses using next generation sequencing and in vitro functional studies using 2-electrode voltage clamp recordings on Xenopus laevis oocytes and a β-lactamase reporter assay in transfected human embryonic kidney (HEK293) cells were performed.

RESULTS

In addition to mild intellectual disability and dysarthria, affected patients presented a tightly consistent early-onset movement disorder combining an exaggerated startle reflex with generalized chorea and multifocal myoclonus. The unreported GRIA3 missense variant c.2477G > A; p.(Gly826Asp) affecting the fourth transmembrane domain of the protein was identified in index patients and their unaffected mothers. Functional studies revealed that variant receptors show decreased current response evoked by agonist (ie, kainic acid and glutamate) and reduced expression on the cell surface in favor of pathogenicity by a loss-of-function mechanism.

CONCLUSIONS

Taken together, our results suggest that apart from known GRIA3-related disorders, an undescribed mutation-specific singular movement disorder does exist. We thus advocate considering GRIA3 mutations in the differential diagnosis of hyperekplexia and generalized chorea with myoclonus. © 2020 International Parkinson and Movement Disorder Society.

Diagnostic approach to neurotransmitter monoamine disorders: experience from clinical, biochemical, and genetic profiles

BACKGROUND AND AIM

To improve the diagnostic work-up of patients with diverse neurological diseases, we have elaborated specific clinical and CSF neurotransmitter patterns.

METHODS

Neurotransmitter determinations in CSF from 1200 patients revealed abnormal values in 228 (19%) cases. In 54/228 (24%) patients, a final diagnosis was identified.

RESULTS

We have reported primary (30/54, 56%) and secondary (24/54, 44%) monoamine neurotransmitter disorders. For primary deficiencies, the most frequently mutated gene was DDC (n = 9), and the others included PAH with neuropsychiatric features (n = 4), PTS (n = 5), QDPR (n = 3), SR (n = 1), and TH (n = 1). We have also identified mutations in SLC6A3, FOXG1 (n = 1 of each), MTHFR (n = 3), FOLR1, and MTHFD (n = 1 of each), for dopamine transporter, neuronal development, and folate metabolism disorders, respectively. For secondary deficiencies, we have identified POLG (n = 3), ACSF3 (n = 1), NFU1, and SDHD (n = 1 of each), playing a role in mitochondrial function. Other mutated genes included: ADAR, RNASEH2B, RNASET2, SLC7A2-IT1 A/B lncRNA, and EXOSC3 involved in nuclear and cytoplasmic metabolism; RanBP2 and CASK implicated in post-traductional and scaffolding modifications; SLC6A19 regulating amino acid transport; MTM1, KCNQ2 (n = 2), and ATP1A3 playing a role in nerve cell electrophysiological state. Chromosome abnormalities, del(8)(p23)/dup(12) (p23) (n = 1), del(6)(q21) (n = 1), dup(17)(p13.3) (n = 1), and non-genetic etiologies (n = 3) were also identified.

CONCLUSION

We have classified the final 54 diagnoses in 11 distinctive biochemical profiles and described them through 20 clinical features. To identify the specific molecular cause of abnormal NT profiles, (targeted) genomics might be used, to improve diagnosis and allow early treatment of complex and rare neurological genetic diseases.

RELN and VLDLR mutations underlie two distinguishable clinico-radiological phenotypes

Pontocerebellar hypoplasias (PCH) are characterized by lack of development and/or early neurodegeneration of cerebellum and brainstem. We report five patients referred for PCH, showing atypical clinical and magnetic resonance imaging (MRI) features suggestive of defects in the Reelin pathway. We screened for mutations in RELN or VLDLR and compared the phenotype of these patients with that of previously reported patients. All patients had profound cerebellar hypoplasia on MRI with peculiar cerebellar morphology, associated with flattened pons and neocortical abnormalities. Patient 1 had profound motor and intellectual disability with moderate lissencephaly suggestive of RELN mutations and was shown to harbor a splicing homozygous RELN mutation. The four other patients had a milder phenotype consistent with CARMQ1 (cerebellar ataxia and mental retardation with or without quadrupedal locomotion). These patients showed mild simplification or thickening of cortical gyration and had VLDLR mutations. Reelin signaling regulates neuronal migration in the developing mammalian brain. VLDLR is a key component of the Reelin pathway. Our patients had a very small and dysplatic cerebellar vermis that should suggest the involvement of these genes. Moreover, differences in clinical severity, involvement of the cerebellar hemispheres, together with the severity of the neocortical defect, enables RELN-mutated patients to be distinguished from VLDLR-mutated patients.

DYRK1A mutations in two unrelated patients

The Dual-specify tyrosine phosphorylation-regulated kinase 1A (DYRK1A) gene has been extensively studied for its role in the pathophysiology of intellectual disability (ID) in Down syndrome. The rise of next generation sequencing (NGS) and array-CGH (aCGH) in diagnostic settings for the evaluation of patients with ID allowed the identification of 17 patients carrying heterozygous genetic aberrations involving DYRK1A to date. The rate of DYRK1A mutations in this population reaches >1% in published NGS studies. The current report aims at further defining the phenotype of this encephalopathy with the detailed report of two unrelated patients. Both patients were boys with developmental delay, febrile seizures, facial dysmorphism and brain atrophy on MRI. Patient #1 had autistic behaviors and micropenis and Patient #2 had stereotypies and microcephaly. NGS analyses identified heterozygous de novo variants in DYRK1A: the c.613C >T (p.Arg205*) nonsense mutation in Patient #1 and the c.932C >T (p.Ser311Phe) missense mutation in Patient #2. Together with previously reported cases, patients with DYRK1A mutations share many clinical features and may have a recognizable phenotype that includes, by decreasing order of frequency: developmental delay or ID with behaviors suggesting autism spectrum disorder, microcephaly, epileptic seizures, facial dysmorphism including ear anomalies (large ears, hypoplastic lobes), thin lips, short philtrum and frontal bossing. Delineation of the phenotype/genotype correlation is not feasible at the moment and will be a challenge for the coming years.

A detailed analysis of the MECP2 gene: prevalence of recurrent mutations and gross DNA rearrangements in Rett syndrome patients

Mutations in the X-linked methyl-CpG-binding protein 2 gene (MECP2) have been found to be a cause of Rett syndrome (RTT). In order to provide further insights into the distribution and the spectrum of mutations, we investigated, in addition to the whole coding sequence, a phylogenetically conserved sequence within the 3' untranslated region (3' UTR) of the MECP2 gene for 55 sporadic RTT, including 47 typical and 8 nonclassical cases. We have developed an approach based on conformation-sensitive gel electrophoresis, sequence analysis and, for the first time, Southern blot analysis. Mutation detection, including unreported gross DNA rearrangements, was achieved in 79% of classical RTT and 25% of nonclassical RTT patients. The high prevalence of recurrent mutations allows us to propose a molecular diagnosis strategy for RTT.

New Types of Stable Aldehydes: Formylphosphane and Formylphosphane Oxide

The reactivity of the formyl group in alpha-phosphorus-substituted aldehydes 1 can be tuned by adjusting the coordination number of the phosphorus atom. When X is a lone pair, the formylphosphanes obtained are stable compounds, whereas when X=O a relatively unstable formylphosphane oxide is produced. R=iPr(2)N, cHex(2)N.

[Total permanent auricular paralysis. Review of the literature apropos of 109 cases]

Analysis of 109 well documented cases of permanent total atrial paralysis reported in the literature illustrated the features of this arrhythmia which is a well defined entity consisting of suppression of all electrical and mechanical activity of both atria lasting for more than 6 months. Standard electrocardiogram reveals junctional bradycardia of about 40 bpm without any visible P waves and narrow supraventricular QRS complexes in 80% of cases. This diagnosis can only be confirmed by meticulous bipolar endocavitary recordings exploring all atrial walls without recording an auriculogram and by right intra-atrial and coronary sinus stimulation which proves to be ineffective. This disease has a male predominance in two-thirds of cases and a familial nature in 18% of cases. Seventy one per cent of affected subjects are under the age of 50 years. In 33% of cases, it is associated with Emery-Dreifuss muscular dystrophy, in which it constitutes a specific sign allowing this dystrophy to be differentiated from all other forms, especially facio-scapulo-humeral myopathy, and in 30% of cases, it is associated with a degenerative disease such as diabetes, amyloidosis or primary cardiomyopathy. Idiopathic dilatation of the right atrium is revealed in 15% of cases. The arrhythmia is responsible for syncope or faintness in 31% of cases, cerebral vascular accidents in 21% of cases and heart failure in 35% of cases. Cardiac activation is dependent on a junctional escape rhythm. The mechanism of the lesion responsible is atrial fibrosis which may extend to the sinoatrial node. The treatment of choice consists of implantation of a VVI or VVIR mode cardiac pacemaker in combination with anticoagulant therapy.

Vertebral-artery dissection following a judo session: a case report

A few days after a judo session, an 11-year-old boy presented with an ischemic stroke with dizziness, aphasia and ataxia. CCT scan revealed a left thalamic infarct. Angiography showed a fibromuscular dysplasia (FMD) of the left vertebral artery probably complicated by dissection. Subsequent evolution was favorable. This observation points out the fact that the association of a cervical pain with neurological signs of vertebrobasilar stroke, especially occurring after a cervical trauma or rotatory motion, should alert to the possibility of vertebral-artery dissection. The diagnosis is mainly based on angiographic criteria. Accurate diagnosis has implications for prognosis and probably for acute medical treatment.

Transplantation of umbilical cord blood in neuroblastoma

It has been shown that umbilical cord blood contains concentrations of hematopoietic progenitor cells equal to those of normal adult bone marrow. We successfully performed transplantation of cord blood combined with a hematopoietic growth factor (rGM-CSF) in a seven year old child suffering from neuroblastoma. Cord blood cells were collected from an HLA identical sibling at the time of delivery and stored in liquid nitrogen. The patient was conditioned with busulfan 600 mg/m2 and cyclophosphamide 200 mg/kg before receiving the thawed cells. There were no immediate side effects. Hematological reconstitution occurred promptly (granulocytes greater than 0.5 x 10(9)/L on day 13, platelets greater than 30 x 10(9)/L on day 40), although at day 10 the child experienced acute grade II cortico-sensitive GvHD. Mixed hematopoietic chimerism was observed 2 months later and complete remission lasted for 8 months.

[Counseling for the prevention of HIV infections in pediatric situations]

Health care professionals who are not adequately informed may have irrational attitudes when caring for HIV-infected pediatric patients. Prevention of contamination rests on thorough knowledge of high-risk pediatric groups and of potentially contaminating situations. In the delivery room and in intensive care settings, a broad set of measures for preventing contamination by blood is needed, whereas in maternity wards preventive steps are needed only during cord stump care. In pediatric departments, care should be taken to avoid injuries with sharp, blood-soiled instruments and to cover all skin lesions. HIV-infected children should be allowed to participate in group activities if they are healthy enough to do so. If an injury should occur, management includes immediate disinfection, reporting, and serial serologic testing, as well as early AZT therapy.

[Chronic intestinal pseudo-obstruction syndrome in infants and associated anomalies]

The authors report 2 cases of functional intestinal pseudo-obstruction in infancy associated with intestinal and urologic anomalies. In the first case many intestinal obstructions occurred from the age of 3 weeks and the boy was operated on at 14 months of age. A short small bowel and an intestinal malrotation were found at surgery; the alimentary canal was completely aperistaltic, and an ileostomy was performed. Further operations were carried out, for obstruction due to adhesions, and lastly to perform another ileostomy. An antenatal diagnosis of megacystis had been made with ultrasonography. In the second case, the pseudo-obstruction syndrome occurred at the age of 1 month, due to a volvulus of the small bowel with malrotation. A second operation, one month later because of lack of intestinal transit showed an aperistaltic bowel and a colostomy was performed. The intestinal continuity was set up again at the age of 9 months and a fractional feeding was started. A megacystis was found during urologic investigations. Growth is correct for both children at 3 years of age. A review of the literature allowed to list the most frequent digestive or extradigestive anomalies associated with this syndrome.

[Capnocytophaga septicemia during bone marrow transplantation. Apropos of 2 cases]

Two cases of septicemia due to Capnocytophaga in pediatric bone marrow recipients are reported. These gram negative rods, which are part of the normal buccal flora, cause periodontitis and localized or systemic infections, usually in immunocompromised hosts. Severe, prolonged neutropenia and mucitis due to chemotherapy and/or radiotherapy are risk factors for this opportunistic infection. Recovery can be achieved with most of the drug combinations including a beta-lactam used in hematology.

[Infections and bone marrow autograft carried out for leukemias in children. Apropos of 47 cases]

This study included 44 children undergoing autologous marrow transplantation for leukemia between August 1979 and June 1987. Three of them received a second transplant. In the phase of neutropenia, 38 children presented with fever. Nineteen septicemia occurred (13 Gram positive cocci, 6 Gram negative bacteria), and 2 interstitial pneumonitis were observed. All children with documented infection or a fever of unknown origin recovered after treatment, except 3, who died from infection. The latest antimicrobial therapy used was a combination of an aminoglycoside and a third generation cephalosporin. When necessary, vancomycin or amphotericin B were added. After engraftment (granulocyte count greater than 0.5 X 10(9)/l) 14 septicemia (which recovered) and 10 herpes zoster infections were observed. Only one patient died of infection (herpes zoster with encephalitis).

[Neurologic effects of acyclovir after an allogenic marrow graft]

On the 4th day of acyclovir treatment for Herpes simplex pneumonia, a 28 month-old girl who had received allogenic marrow transplant for stage IV neuroblastoma presented with severe neurologic disorders including coma and choreic movements. These symptoms disappeared 9 days after acyclovir was stopped. The disturbance in acyclovir kinetics because of acute renal failure and/or a cerebral cortex atrophy might explain the poor neurologic tolerance of acyclovir. This reversible neurologic involvement on a prone patient should be known as a differential diagnosis of Herpes simplex encephalitis.

[Importance of the study of allergy and determination of the HLA group in the lipoid nephrosis in children. Study of 8 cases]

Eight children with steroid-response nephrotic syndrome were investigated to study the relation-ship between steroid responsive syndrome, allergy and HLA-antigens. Six of them had clinical and/or biological allergic symptoms. The allergen was identified in four out of six cases (grass-pollen 2 cases, house dust 1 case, frullania 1 case). Six children had DR7 HLA-antigen, five had B12 antigen. Three of the four children with cortico-dependent nephrotic syndrome have associated B12-DR7 HLA antigens. Search of an allergen seems to be of interest in children with steroid-responsive nephrotic syndrome, since eviction of the allergen may be proposed as a complement to cortico-therapy.