GM3 synthase deficiency in non-Amish patients

PURPOSE

Biallelic loss-of-function variants in ST3GAL5 cause GM3 synthase deficiency (GM3SD) responsible for Amish infantile epilepsy syndrome. All Amish patients carry the homozygous p.(Arg288Ter) variant arising from a founder effect. To date only 10 patients from 4 non-Amish families have been reported. Thus, the phenotypical spectrum of GM3SD due to other variants and other genetic backgrounds is still poorly known.

METHODS

We collected clinical and molecular data from 16 non-Amish patients with pathogenic ST3GAL5 variants resulting in GM3SD.

RESULTS

We identified 12 families originating from Reunion Island, Ivory Coast, Italy, and Algeria and carrying 6 ST3GAL5 variants, 5 of which were novel. Genealogical investigations and/or haplotype analyses showed that 3 of these variants were founder alleles. Glycosphingolipids quantification in patients' plasma confirmed the pathogenicity of 4 novel variants. All patients (N = 16), aged 2 to 12 years, had severe to profound intellectual disability, 14 of 16 had a hyperkinetic movement disorder, 11 of 16 had epilepsy and 9 of 16 had microcephaly. Other main features were progressive skin pigmentation anomalies, optic atrophy or pale papillae, and hearing loss.

CONCLUSION

The phenotype of non-Amish patients with GM3SD is similar to the Amish infantile epilepsy syndrome, which suggests that GM3SD is associated with a narrow and severe clinical spectrum.

Palliative Care in SMA Type 1: A Prospective Multicenter French Study Based on Parents' Reports

Spinal muscular atrophy type 1 (SMA-1) is a severe neurodegenerative disorder, which in the absence of curative treatment, leads to death before 1 year of age in most cases. Caring for these short-lived and severely impaired infants requires palliative management. New drugs (nusinersen) have recently been developed that may modify SMA-1 natural history and thus raise ethical concerns about the appropriate level of care for patients. The national Hospital Clinical Research Program (PHRC) called "Assessment of clinical practices of palliative care in children with Spinal Muscular Atrophy Type 1 (SMA-1)" was a multicenter prospective study conducted in France between 2012 and 2016 to report palliative practices in SMA-1 in real life through prospective caregivers' reports about their infants' management. Thirty-nine patients were included in the prospective PHRC (17 centers). We also studied retrospective data regarding management of 43 other SMA-1 patients (18 centers) over the same period, including seven treated with nusinersen, in comparison with historical data from 222 patients previously published over two periods of 10 years (1989-2009). In the latest period studied, median age at diagnosis was 3 months [0.6-10.4]. Seventy-seven patients died at a median 6 months of age[1-27]: 32% at home and 8% in an intensive care unit. Eighty-five percent of patients received enteral nutrition, some through a gastrostomy (6%). Sixteen percent had a non-invasive ventilation (NIV). Seventy-seven percent received sedative treatment at the time of death. Over time, palliative management occurred more frequently at home with increased levels of technical supportive care (enteral nutrition, oxygenotherapy, and analgesic and sedative treatments). No statistical difference was found between the prospective and retrospective patients for the last period. However, significant differences were found between patients treated with nusinersen vs. those untreated. Our data confirm that palliative care is essential in management of SMA-1 patients and that parents are extensively involved in everyday patient care. Our data suggest that nusinersen treatment was accompanied by significantly more invasive supportive care, indicating that a re-examination of standard clinical practices should explicitly consider what treatment pathways are in infants' and caregivers' best interest. This study was registered on clinicaltrials.gov under the reference NCT01862042 (https://clinicaltrials.gov/ct2/show/study/NCT01862042?cond=SMA1&rank=8).

Correction to: In vitro prediction of stop-codon suppression by intravenous gentamicin in patients with cystic fibrosis: a pilot study

The original article [1] contains errors in Table 1 affecting some of the presented oligonucleotide sequences and readthrough values in Table 1.

Pulmonary alveolar proteinosis in children on La Réunion Island: a new inherited disorder?

Background

Pulmonary alveolar proteinosis (PAP) is very rare in children. Only a few small series have been published, with little information about long-term progression. The objective of our study was to describe the clinical, radiological and pathological features, and the long-term course of PAP in a cohort of 34 children from La Réunion Island.

Methods

Data were retrospectively collected from medical files. Radiological and pathological elements were reviewed by two pediatric radiologists and three pathologists, respectively.

Results

Thirteen cases were familial and 32/34 (94%) cases were family connected. Disease onset occurred in the first six months of life in 82% of the patients. Thoracic computed tomography scans showed the typical “crazy-paving” pattern in 94% of cases. Respiratory disease was associated with a liver disorder, with the detection of liver enlargement at diagnosis in 56% of cases. The course of the disease was characterized by frequent progression to chronic respiratory insufficiency, accompanied by the appearance of cholesterol granulomas and pulmonary fibrosis. Overall prognosis was poor, with a mortality of 59% and an overall five-year survival rate from birth of 64%. Whole-lung lavages were performed in 21 patients, with no significant effect on survival. Liver disease progressed to cirrhosis in 18% of children, with no severe complication.

Conclusions

PAP in children from la Réunion Island is characterized by an early onset, associated liver involvement, poor prognosis and frequent progression to lung fibrosis, despite whole-lung lavages treatment. The geographic clustering of patients and the detection of many familial links between most of the cases strongly suggest a genetic etiology, with an autosomal recessive mode of inheritance.

Two patients with imported acute neuroschistosomiasis due to Schistosoma mansoni

We report the case of two brothers who returned from Madagascar presenting all the acute phase symptoms of a primary invasive Schistosoma mansoni infection, together with brain involvement characterized by acute encephalitis. This rarely described issue should be considered in travelers returning from endemic areas with acute neurological symptoms.

In vitro prediction of stop-codon suppression by intravenous gentamicin in patients with cystic fibrosis: a pilot study

BACKGROUND

Cystic fibrosis (CF) is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which acts as a chloride channel activated by cyclic AMP (cAMP). The most frequent mutation found in 70% of CF patients is F508del, while premature stop mutations are found in about 10% of patients. In vitro aminoglycoside antibiotics (e.g. gentamicin) suppress nonsense mutations located in CFTR permitting translation to continue to the natural termination codon. Pharmacologic suppression of stop mutations within the CFTR may be of benefit to a significant number of patients. Our pilot study was conducted to determine whether intravenous gentamicin suppresses stop codons in CF patients and whether it has clinical benefits.

METHODS

A dual gene reporter system was used to determine the gentamicin-induced readthrough level of the most frequent stop mutations within the CFTR in the French population. We investigated readthrough efficiency in response to 10 mg/kg once-daily intravenous gentamicin perfusions in patients with and without stop mutations. Respiratory function, sweat chloride concentration, nasal potential difference (NPD) and CFTR expression in nasal epithelial cells were measured at baseline and after 15 days of treatment.

RESULTS

After in vitro gentamicin incubation, the readthrough efficiency for the Y122X mutation was at least five times higher than that for G542X, R1162X, and W1282X. In six of the nine patients with the Y122X mutation, CFTR immunodetection showed protein at the membrane of the nasal epithelial cells and the CFTR-dependent Cl- secretion in NPD measurements increased significantly. Respiratory status also improved in these patients, irrespective of the gentamicin sensitivity of the bacteria present in the sputum. Mean sweat chloride concentration decreased significantly and normalised in two patients. Clinical status, NPD and sweat Cl- values did not change in the Y122X patients with no protein expression, in patients with the other stop mutations investigated in vitro and those without stop mutations.

CONCLUSION

Suppression of stop mutations in the CFTR gene with parenteral gentamicin can be predicted in vitro and is associated with clinical benefit and significant modification of the CFTR-mediated Cl- transport in nasal and sweat gland epithelium.

A Frequent Large Rearrangement in theCFTRGene in Cystic Fibrosis Patients from Reunion Island

Reunion Island is a French province, 800 km east of Madagascar and 200 km west of Mauritius. On Reunion Island, the birth prevalence of cystic fibrosis (CF) is particularly high in the population of European origin, approximately 1:1000. In a previous study, we demonstrated that the screening of the 27 exons of the CF transmembrane conductance regulator (CFTR) gene by denaturing high-pressure liquid chromatography (DHPLC) in 114 CF families allowed the detection of about 93% of the molecular defects present on Reunion Island. Unidentified CF mutations may lie in introns or in regulatory regions that are not routinely investigated, or may correspond to gene rearrangements such as large, heterozygous deletions that escape detection using current PCR-based techniques. Using a combination of different methods (such as multiplex ligation-dependent probe amplification), 6 of the 13 unidentified CF alleles (46%) were found to harbor a deletion of 5288 bp, spanning from exon 17a to 18. Identification and examination of the breakpoint sequences showed that this deletion is different from the 3120+1kbdel8.6Kb previously found in the Palestinian Arabs. The chromosomes bearing IVS16+3316_IVS18+644del5288 did not have a common extragenic haplotype. Clinical evaluation of homozygotes (2 unrelated patients) and compound heterozygotes indicated that this deletion represents a severe mutation associated with positive sweat chloride test, pancreatic insufficiency, and early age at diagnosis.

Spectrum of CFTR mutations on Réunion Island: impact on neonatal screening

The large heterogeneity in the cystic fibrosis (CF) gene is the main difficulty for genotype characterization. Numerous studies have reported considerable variations in frequencies of CF transmembrane conductance regulator (CFTR) mutations in different populations, such as African, Asian, or European populations. To completely characterize the spectrum of mutations in the CFTR gene in the Réunion Island population, we screened 228 CF chromosomes using denaturing high-pressure liquid chromatography and denaturing gradient gel electrophoresis following by direct sequencing. We identified 27 mutations, accounting for 93% of CF chromosomes. They included three novel mutations (M1T, 3121-3C-->G, and L1324P), which are described in this paper. The detection of such a high proportion of Réunion Island CFTR mutations is important for improving neonatal screening of CF on Réunion Island.

Down-regulation of the anti-inflammatory protein annexin A1 in cystic fibrosis knock-out mice and patients

Cystic fibrosis is a fatal human genetic disease caused by mutations in the CFTR gene encoding a cAMP-activated chloride channel. It is characterized by abnormal fluid transport across secretory epithelia and chronic inflammation in lung, pancreas, and intestine. Because cystic fibrosis (CF) pathophysiology cannot be explained solely by dysfunction of cystic fibrosis transmembrane conductance regulator (CFTR), we applied a proteomic approach (bidimensional electrophoresis and mass spectrometry) to search for differentially expressed proteins between mice lacking cftr (cftr(tm1Unc), cftr-/-) and controls using colonic crypts from young animals, i.e. prior to the development of intestinal inflammation. By analyzing total proteins separated in the range of pH 6-11, we detected 24 differentially expressed proteins (>2-fold). In this work, we focused on one of these proteins that was absent in two-dimensional gels from cftr-/- mice. This protein spot (molecular mass, 37 kDa; pI 7) was identified by mass spectrometry as annexin A1, an anti-inflammatory protein. Interestingly, annexin A1 was also undetectable in lungs and pancreas of cftr-/- mice, tissues known to express CFTR. Absence of this inhibitory mediator of the host inflammatory response was associated with colonic up-regulation of the proinflammatory cytosolic phospholipase A2. More importantly, annexin A1 was down-regulated in nasal epithelial cells from CF patients bearing homozygous nonsense mutations in the CFTR gene (Y122X, 489delC) and differentially expressed in F508del patients. These results suggest that annexin A1 may be a key protein involved in CF pathogenesis especially in relation to the not well defined field of inflammation in CF. We suggest that decreased expression of annexin A1 contributes to the worsening of the CF phenotype.

Cystic fibrosis at the Reunion Island (France): spectrum of mutations and genotype-phenotype for the Y122X mutation

BACKGROUND

The Reunion Island is a French administrative department located in the Indian Ocean between the islands of Madagascar and Mauritius. Its population is known to be at a high risk of cystic fibrosis (CF).

METHODS

Data concerning all CF patients born at the Reunion Island was extracted from the French CF Registry. Twenty-eight DeltaF508/DeltaF508, 17 Y122X/DeltaF508, and 11 Y122X/Y122X were included in a genotype-phenotype study.

RESULTS

The detection rate of the CFTR mutations was 83% among the CF patients born at the Reunion Island. Three CFTR mutations accounted for 75% of the detected CF alleles at the Reunion Island (DeltaF508, Y122X, and 3120 + 1G-->A.). The DeltaF508/DeltaF508, DeltaF508/Y122X, and Y122X/Y122X genotypes accounted for 60.2% of the CF patients. Patients carrying at least one Y122X mutation were pancreatic insufficient, had high sweat chloride values and significantly lower anthropometric measures. The mean anthropometric values in all three groups were lower that in the whole CF population followed in "continental" France. This may reflect the poor compliance and even the refusal of treatment noted by the clinicians.

CONCLUSIONS

The distribution of CFTR mutations could be explained by the history of the Reunion Island: admixture of French settlers, African and Asian populations, founder effect and isolation followed by genetic drift. The Y122X allele appears to be associated with a severe phenotype.

Toxoplasmose maternelle anté-conceptionnelle et choriorétinite chez des jumelles

A maternal toxoplasmosis before conception is exceptionally transmitted to the fetus. We report an observation of twin sisters who presented congenital toxoplasmosis with chorioretinitis detected at nine months of age. The anamnesis revealed that the mother had had toxoplasmosis one month before conception. In the event of preconceptual infections, we propose fetal ultrasonography, histological examination of the placenta at delivery, as well as a pediatric follow-up of the infants (serological samples every month, cranial ultrasonography, fundus oculi).

[Clinical aspects and genetic specificities of cystic fibrosis in Reunion Island]

OBJECTIVES

Evaluation of the phenotype-genotype correlation of a specific mucoviscidosis mutation, "Y122X", in Reunion Island. This mutation represents 25% of our cases.

PATIENTS AND METHODS

Retrospective study of a cohort of 84 children presenting cystic fibrosis (CF) during a 5-year period (1994-1998). Diagnosis was based on one or two identified genetic mutations and/or minimum two abnormal chloride sweat tests (Cl > 70 mmol/l). Follow-up of this cohort was performed in the two referral centers of the Island following the French national guidelines (INSERM U 155).

RESULTS

In our population, we identified 10 mutations, of which three of them represented more than 80% of the cases: Delta F508 (51.8%), Y122X (24.4%) and 3120 + 1G --> A (4.8%). The authors report clinical significant differences in children with the homozygote mutation Y122X as compared with children presenting the Delta F508 CF-mutation: failure to thrive affecting mainly the height with, paradoxically, a relatively normal weight development, and a better pulmonary function.

CONCLUSION

The frequent Y122X CF-mutation reported in "la Reunion" seems to affect mainly height in children with a relatively good nutritional outcome. This failure to thrive does not seem to be of digestive origin. These results suggest that growth gene(s) located nearby the cystic fibrosis transmembrane conductance regulator (CFTR) may have suffered the same segregation than the Y122X mutation or that clusters of this specific Caucasian population known as "petits blancs" in la Reunion are smallest for ethnic reasons.

[Hypernatremic dehydration and breastfeeding]

Neonatal hypernatremic dehydration due to breast feeding was rarely reported in the French-language literature.

CASE REPORT

The authors report hypernatremic dehydration in a 10-day-old exclusively breast-fed infant. The course was favorable. Insufficient breast milk production has been reported for 30 years.

CONCLUSION

Early discharge from maternity units is frequent nowadays. Breast-fed newborns without a positive weight gain at discharge should be checked for their weight within the first ten days of life.

[Severe anorexia in infants in Reunion: a new autosomal recessive disease?]

BACKGROUND

Infantile anorexia is usually considered as a psychogenic disorder with benign prognosis. However, unusually severe characteristics of infantile anorexia, seen in the south of the island, seem to us in favor of a new metabolic etiology.

POPULATION AND METHODS

Among 38 known cases, we retrospectively studied the best documented observations of 24 children admitted over the last 25 years to our institution.

RESULTS

The sex ratio was ten females and 14 males. Twenty-three of the 24 infants lived in formerly isolated localities of the island where other hereditary diseases have been observed with an unusually high frequency. The family pedigrees favoured an autosomal recessive heredity. Severe anorexia, accompanied by irrepressible vomiting (91%), appeared at the age of 8.5 months +/- 3.5. Parenteral (54.2%) or enteral (54.2%) feeding was necessary but did not always avoid death, which occurred in 45.8% of the cases at the age of 24 months +/- 3.5. All of the children which survived had neurological disorders (pyramidal syndrome, ataxia, laryngeal palsy, mental retardation, seizures) which occurred sometimes at an early stage. The investigations did not allow the identification of any known cause.

DISCUSSION

The elevated level of lactic acid in the cerebral spinal fluid seemed to indicate a possible mitochondrial disorder, eventually a mutation of an autosomal gene of the pyruvate dehydrogenase complex because of the normal lactate/pyruvate ratio, but enzymatic activities were normal. The cerebral MRI showed features of leukodystrophy. On the other hand, the elevated level of plasma serotonin seemed to indicate a disorder of the serotonin metabolism, for which an animal model exists.

CONCLUSION

We propose to name this new syndrome by the acronym 'RAVINE' which associates Reunion, Anorexia, Vomiting which is Irrepressible, and Neurological signs. Linkage study might allow the localization and isolation of a gene and allow one to start understanding the biological mechanism which we suspect to be an hereditary neurobiological eating disorder.

[MELAS syndrome in a five year-old child: clinical, biological and genetic characteristics]

BACKGROUND

MELAS syndrome is a rare mitochondrial cytopathy; its diagnosis can be difficult.

CASE REPORT

A 6-month-old boy presented with febrile seizures, possibly due to viral meningitis. At 7 months, he developed myoclonia and "brain attacks" and, subsequently, myoclonical attacks, regression of psychomotor and mental acquisitions, and progressive visual loss. The ratio of lactatorachia/lactacidemia was increased. The molecular genetic analysis showed an heteroplasmic point mutation with A-to-G mutation at nucleotide 3243 of the mitochondrial tRNA(leu) (UUR) gene. He was the second child of a mother having frequent headaches. His great aunt, a sister of his maternal grandmother, was mentally retarded and had frequent epileptic seizures and hemiparesy since her childhood.

CONCLUSION

Any unusual neurological symptom, particularly when combined with "illegitimate" symptoms, should lead to search for a mitochondrial cytopathy.

[Angiostrongylus in the infant at Reunion and Mayotte. Apropos of 3 cases of eosinophilic meningitis including 1 fatal radiculomyeloencephalitis with hydrocephalus]

BACKGROUND

Eosinophilic meningitis caused by Angiostrongylus cantonensis is widespread in Southeast Asia and Pacific islands. Adults develop a transient meningitis with a benign course but severe or fatal disease may occur in pediatric patients. CASE REPORT 1: A 11 months old boy living in Mayotte island was hospitalized some days after fever and skin rash with seizure status, coma, flaccid quadriplegia, absence of deep tendon reflexes, urinary retention and anal incontinence. Eosinophilia was observed in peripheral blood and in the cerebrospinal fluid. Secondary, he developed a triventricular hydrocephalus treated by a ventriculoperitoneal shunt. After 3 weeks, the child died. Retrospectively, the diagnosis of angiostrongylus infection was established with the help of serology. CASE REPORTS 2 AND 3: Two infants, 10 and 11 months old boys, living in Reunion island, developed fever and vomitings, irritability and, for one of them, a unilateral sixth cranial nerve palsy. There was eosinophilia in the peripheral blood and in the cerebrospinal fluid. All symptoms progressively disappeared with complete recovery. The suspected diagnosis of angiostrongylus infection was confirmed by the serology.

CONCLUSION

We report the first case of Angiostrongylus cantonensis infection in the French island of Mayotte (Comoro Islands) and we confirm the presence of this disease in Reunion island. In this Indian Ocean area, eosinophilic meningitis occurs most of the time in infants with sometimes severe radiculomyeloencephalitic forms. The origin of these occasionally massive infections is the giant African snail Achatina fulica. For a child with meningitis living in Reunion or Mayotte, or coming back from these 2 islands, Angiostrongylus cantonensis infection must be evoked, especially if there is a blood eosinophilia. Since efficiency of antiparasitic treatment is nowadays not proved, information must be given to people living in exposed areas in view to limit incidence of this disease.

[Angiostrongylosis in infants in Reunion and Mayotte. Apropos of 3 cases of eosinophilic meningitis including 1 fatal radiculo-myeloencephalitis with hydrocephalus]

BACKGROUND

Eosinophilic meningitis caused by Angiostrongylus cantonensis is widespread in Southeast Asia and Pacific islands. Adults develop a transient meningitis with a benign course but severe or fatal disease may occur in pediatric patients.

CASE REPORT

Case 1. A 11-month-old boy living in Mayotte island was hospitalized a few days with fever and skin rash following by seizure, coma, flaccid quadraplegia, absence of deep tendon reflexes, urinary retention and anal incontinence. Eosinophilia was observed in peripheral blood and cerebrospinal fluid. He further developed a triventricular hydrocephalus treated by ventriculoperitoneal shunt. The child died 3 weeks later. A serodiagnosis of angiostrongylus infestation was restrospectively established. Case reports 2 and 3.-Two infants, 10 and 11-month-old-boys, living in Reunion island, developed fever and vomitings, irritability and, for one of them, unilateral sixth cranial nerve palsy. There was eosinophilia in the peripheral blood and in the cerebrospinal fluid. All symptoms progressively disappeared with complete recovery. The suspected diagnosis of angiostrongylus infestation was confirmed by the serology.

CONCLUSION

We report the first case of Angiostrongylus cantonensis infection in the French island of Mayone (Comoro Islands) and we confirm the presence of this disease in Reunion island. In this Indian Ocean area, eosinophilic meningitis occurs most of the time in infants with sometimes severe radiculomyeloencephalitic forms.

A splicing mutation in intron 16 of the cystic fibrosis transmembrane conductance regulator gene, associated with severe disease, is common on Reunion Island

In addition to the frequent delta F508 and Y122X mutations on cystic fibrosis (CF) chromosomes of patients from Reunion Island, one splicing mutation, 3120+1G-->A is observed relatively frequently (12.5%) in this group, in comparison with the French metropolitan population (<0.001 %). This mutation, disrupting the 5' splice donor site of intron 16, can be detected easily by restriction enzyme BstNI digestion. In 2 CF patients homozygous for this mutation, the clinical pattern was severe, with both pancreatic insufficiency and respiratory symptoms.