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Prader-Willi syndrome (PWS) is a rare genetic neurodevelopmental disorder with a characteristic behavioural phenotype. A multidisciplinary approach to care is required to prevent multiple medical complications in individuals affected by PWS. The aim of this study was to describe the rehabilitation, medical care, educational and social support provided to school-aged French PWS patients with varying neuropsychological profiles. Data were obtained from a French multicentre study that included patients aged 4-20 years with diverse genetic syndromes. Nineteen PWS subjects with a mean age of 9.2 years were included. The mean full-scale intellectual quotient (IQ) was 58 (Wechsler scale). There were frequent dissociations between verbal and performance IQ that were not associated with a specific profile. We also observed lower autonomy and communication scores (5.3 years and 5.9 years equivalent, respectively, Vineland scale), the absence of hyperactivity (Conners scale), and the presence of behavioural abnormalities (CBCL scale). Multidisciplinary medical supervision was generally coordinated by the paediatric endocrinologist and did not always include follow-up with all of the recommended specialists, in particular with a paediatric psychiatrist. Analysis of multidisciplinary rehabilitation conducted in public and private-sector establishment revealed failings in psychological support, occupational therapy and dietary follow-up. Regarding education, most children younger than 10 years were in normal schools, while older individuals were often cared for in medico-social institutions. In conclusion, children and adolescents with PWS generally received appropriate care. Though there have been considerable improvements in the management of children with PWS, reference centres should continue reinforcing the coordination of multidisciplinary supervision., (Copyright © 2020. Published by Elsevier Masson SAS.)

The MTOR gene encodes the mechanistic target of rapamycin (mTOR), which is a core component of the PI3K-AKT-mTOR signaling pathway. Postzygotic MTOR variants result in various mosaic phenotypes, referred to in OMIM as Smith-Kinsgmore syndrome or focal cortical dysplasia. We report here the case of a patient, with an MTOR mosaic gain-of-function variant (p.Glu2419Lys) in the DNA of 41% skin cells, who received compassionate off-label treatment with everolimus for refractory epilepsy. This 12-year-old-girl presented with psychomotor regression, intractable seizures, hypopigmentation along Blaschko's lines (hypomelanosis of Ito), asymmetric regional body overgrowth, and ocular anomalies, as well as left cerebral hemispheric hypertrophy with some focal underlying migration disorders. In response to the patient's increasingly frequent epileptic seizures, everolimus was initiated (after approval from the hospital ethics committee) at 5 mg/day and progressively increased to 12.5 mg/day. After 5 months of close monitoring (including neuropsychological and electroencephalographic assessment), no decrease in seizure frequency was observed. Though the physiopathological rationale was good, no significant clinical response was noticed under everolimus treatment. A clinical trial would be needed to draw conclusions, but, because the phenotype is extremely rare, it would certainly need to be conducted on an international scale., (Copyright © 2020. Published by Elsevier Masson SAS.)

Background and Objective: Whole-exome sequencing (WES) has now entered medical practice with powerful applications in the diagnosis of rare Mendelian disorders. Although the usefulness and cost-effectiveness of WES have been widely demonstrated, it is essential to reduce the diagnostic turnaround time to make WES a first-line procedure. Since 2011, the automation of laboratory procedures and advances in sequencing chemistry have made it possible to carry out diagnostic whole genome sequencing from the blood sample to molecular diagnosis of suspected genetic disorders within 50 h. Taking advantage of these advances, the main objective of the study was to improve turnaround times for sequencing results., Methods: WES was proposed to 29 patients with severe undiagnosed disorders with developmental abnormalities and faced with medical situations requiring rapid diagnosis. Each family gave consent. The extracted DNA was sequenced on a NextSeq500 (Illumina) instrument. Data were analyzed following standard procedures. Variants were interpreted using in-house software. Each rare variant affecting protein sequences with clinical relevance was tested for familial segregation., Results: The diagnostic rate was 45% (13/29), with a mean turnaround time of 40 days from reception of the specimen to delivery of results to the referring physician. Besides permitting genetic counseling, the rapid diagnosis for positive families led to two pre-natal diagnoses and two inclusions in clinical trials., Conclusions: This pilot study demonstrated the feasibility of rapid diagnostic WES in our primary genetics center. It reduced the diagnostic odyssey and helped provide support to families., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Oral-facial-digital syndrome type VI (OFD VI) is characterized by the association of malformations of the face, oral cavity and extremities, distinguished from the 12 other OFD syndromes by cerebellar and metacarpal abnormalities. Cerebellar malformations in OFD VI have been described as a molar tooth sign (MTS), thus, including OFD VI among the "Joubert syndrome related disorders" (JSRD). OFD VI diagnostic criteria have recently been suggested: MTS and one or more of the following: 1) tongue hamartoma(s) and/or additional frenula and/or upper lip notch; 2) mesoaxial polydactyly of hands or feet; 3) hypothalamic hamartoma. In order to further delineate this rare entity, we present the neurological and radiological data of 6 additional OFD VI patients. All patients presented oral malformations, facial dysmorphism and distal abnormalities including frequent polydactyly (66%), as well as neurological symptoms with moderate to severe mental retardation. Contrary to historically reported patients, mesoaxial polydactyly did not appear to be a predominant clinical feature in OFD VI. Sequencing analyzes of the 14 genes implicated in JSRD up to 2011 revealed only an OFD1 frameshift mutation in one female OFD VI patient, strengthening the link between these two oral-facial-digital syndromes and JSRD., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Poikiloderma occurs in a number of hereditary syndromes, the best known of which is Rothmund-Thomson syndrome (RTS). Differential diagnoses include Dyskeratosis Congenita (DC) with high genetic heterogeneity and Clericuzio-type Poikiloderma with Neutropenia (CPN) due to mutations in the C16orf57 gene. Mutations in the RECQL4 gene are only observed in two thirds of RTS patients. In this study, 10 patients referred for syndromic poikiloderma and negative for RECQL4 sequencing analysis were investigated for C16orf57 mutations. Two C16orf57 heterozygous nonsense mutations (p.W81X and p.Y89X) were identified in a 5-year-old female child presenting with generalized poikiloderma, dental dysplasia, gingivitis, nail dystrophy, palmoplantar keratoderma and pachyonychia of the great toenails. Previously undetected and silent neutropenia was evidenced after C16orf57 molecular analysis. Neutropenia was absent in the C16orf57-negative patients. This report confirms that neutrophil count should be performed in all patients with poikiloderma to target the C16orf57 gene sequencing analysis, prior to RECQL4 analysis., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

We report the case of a 26-month-old boy with mental retardation, facial dysmorphism, childhood feeding difficulties, short stature, bilateral cryptorchidism, micropenis, and heart defect. Endocrinal evaluation revealed complete growth hormone deficiency (GHD) and gonadotropic deficiency, and pituitary magnetic resonance imaging showed partial pituitary stalk interruption syndrome (PSIS). A de novo 493 kb microdeletion on chromosome 17q21.31 was identified using array comparative genomic hybridization (array-CGH) analysis. This is the first report of PSIS in the phenotypical spectrum of 17q21.31 microdeletion syndrome, although other midline abnormalities have previously been described. Our report suggests that GHD should be investigated in patients with 17q21.31 microdeletion syndrome and short stature, defined by a body height below - 2 standard deviation scores (SDS) for age and sex. This finding also opens new avenues of research on the etiopathogenesis of PSIS, for which the genetic mechanisms remain unknown., (Copyright © 2011 Elsevier Masson SAS. All rights reserved.)

X-linked periventricular nodular heterotopia (PH) is a neuronal migration disorder caused by mutations in the gene encoding filamin A (FLNA). High phenotypic diversity, ranging from PH to otopalatodigital syndrome and frontometaphyseal dysplasia has been described in association with FLNA mutations. Extra-neurological features including cardiovascular abnormalities, coagulopathy, skeletal dysplasia and joint hypermobility have sometimes been described in patients with PH. Respiratory manifestations have not been associated with FLNA disorders with the exception of tracheal stenosis and pulmonary hypoplasia associated with frontometaphyseal dysplasia and Melnick-Needles syndrome. Here, we report on a male patient aged 6 years presenting with a mosaic nonsense mutation c.994delG within the FLNA gene, PH and severe congenital lung disease comprising bilateral atelectasis, lung cysts, tracheobronchomalacia, pulmonary arterial hypertension and long-term oxygen dependence; histology of resected lung showed panpulmonary emphysema with marked reduction of bronchial cartilage. Rare male patients with PH and FLNA mutations have already been reported, usually with early lethality. These observations suggest the possibility of a link between FLNA mutations and congenital lung disease. A prospective study of patients with PH and FLNA mutations would be helpful in order to test this hypothesis., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

Interstitial deletions involving the 15q21.1 band are very rare. Only 4 of these cases have been studied using molecular cytogenetic techniques in order to confirm the deletion of the whole FBN1 gene. The presence of clinical features of the Marfan syndrome (MFS) spectrum associated with mental retardation has been described in only 2/4 patients. Here we report on a 16-year-old female referred for suspicion of MFS (positive thumb and wrist sign, scoliosis, joint hyperlaxity, high-arched palate with dental crowding, dysmorphism, mitral insufficiency with dystrophic valve, striae). She had therefore 3 minor criteria according to the Ghent nosology. She also had speech disabilities but could follow normal school training. Direct sequencing of the FBN1, TGFBR1 and TGFBR2 genes was negative. MLPA revealed a genomic deletion of the whole FBN1 gene, confirmed by loss of heterozygosity of maternal alleles for several microsatellite markers surrounding the FBN1 gene. The deletion was confirmed by FISH using a FBN1 probe and was not found in the parents. Array-CGH permitted to define a 2.97 Mb deletion, which was the smallest 15q microdeletion including FBN1. Contrary to the other published observations, our proband does not exhibit mental retardation, but neuropsychological evaluations revealed an attention deficit as well as a deficit in information-processing speed. Haploinsufficiency of FBN1 is likely to contribute to the presence of MFS features. However, attenuated features could be explained because disturbances of TGF-beta signalling associated with FBN1 mutations do not exert full phenotypic effect through simple haploinsufficiency. Phenotypic variability in other patients with interstitial deletions including 15q21.1 band may reflect differences in deletion size and/or cys/trans modifying factors., (Copyright 2010 Elsevier Masson SAS. All rights reserved.)

Here we describe the clinical, histopathological and molecular studies of a female proband that died at 2 months of age in the context of a syndromic polymicrogyria. There was no significant family history. Clinical and radiological features included poor contact, cleft palate, facial dysmorphic features with frontal bossing, down-slanting and small palpebral fissures, inferior epicanthic folds, low-set and malformed ears, flat nose, retrognathism and short neck, minor limb anomalies, polymicrogyria that appear more severe in the perisylvian regions and cerebellar vermis hypoplasia. Autopsy findings revealed a patent foramen ovale with persistent left superior vena cava, left renal hypoplasia and microphthalmia. This description does not fit with any of the known syndromes with polymicrogyria and cytogenetic analyses including standard and high resolution chromosome analyses, telomeric FISH studies and array-CGH were normal. Consequently, the reported features in this child are unique and are likely to represent a new syndrome.

We report a new case of megalencephaly and polymicrogyria with post-axial polydactyly and hydrocephalus (MPPH syndrome) in an 18-month-old girl. She was the first child of healthy non-consanguineous parents and measurements at birth were +3 standard deviations (S.D.) for weight, +2 S.D. for length and +4 S.D. for OFC. Ultrasound scan at 24 weeks of gestation (WG) showed mild ventriculomagaly with unique umbilical artery and dacryocystocele. Clinical examination at birth revealed macrosomia with macrocephaly, facial dysmorphism, post-axial polydactyly at the right hand and both feet, and axial hypotonia with hypertonic arms and legs. At 18 months of age, weight was +2 S.D., length was +2 S.D. and OFC was +4 S.D. She remained hypertonic, could not sit and had no hand use. Cerebral magnetic resonance imaging showed stable ventriculomegaly and polymicrogyria located on the frontal and perisylvian region with white matter hypersignal on T2-weighted images. There was no associated visceral malformation. Standard and high-resolution cytogenetic examination, telomeric FISH and array-CGH studies were normal. This case represents the sixth observation of MPPH syndrome as described by Mirzaa et al. in 2004. We provide further neurological follow-up since three out of five index patients were aged 6 months or less. We postulate that macrosomia at birth might be a major feature (five/six cases), with advanced bone age in the two/two investigated cases. White matter abnormalities might be an occasional feature of this syndrome (three/six cases), as well as dacryocystocele, if not coincidental (one/six case). The mode of inheritance of this syndrome remains unknown since there was no significant family history in all reported cases. The search for infracytogenetic chromosomal imbalance was unsuccessful.

The VATER association of vertebral anomalies (V), anal atresia (A), esophageal atresia and/or tracheo-esophageal fistula (TE), radial and renal anomalies (R) is a common congenital association of unknown origin with probably heterogeneous causes. Here, we report on a girl presenting with pre- and postnatal growth retardation, esophageal atresia, vertebral and costal anomalies and a unilateral radial defect, consistent with the diagnosis of VATER association. In the first month of life, she presented with failure to thrive, severe episodes of hypoglycemia, liver dysfunction and high levels of lactate, which prompted us to perform metabolic screening. A complex IV respiratory chain deficiency (RCD) was diagnosed on a liver biopsy. The respiratory chain defect was not observed in skin fibroblasts. No mtDNA point mutation or deletion was identified. The girl is now 9 years old and has a normal mental development but persistent feeding difficulties and moderate hyperlactatemia. To our knowledge, this is the second report of VATER association with mitochondrial disorder. In a previous report, a VACTERL association was observed in a girl with the mitochondrial A3243G point mutation. The association of VATER phenotype with a mitochondrial disorder may be coincidental but could also suggest that the presence of multiple malformations is the result of the antenatal expression of RCD.