Finger creases lend a hand in Kabuki syndrome.

International audienceKabuki syndrome (KS) is a rare syndrome associating malformations with intellectual deficiency and numerous visceral, orthopedic, endocrinological, immune and autoimmune complications. The early establishment of a diagnostic of KS leads to better care of the patients and therefore prevents complications such as perception deafness, severe complications of auto-immune diseases or obesity. However, the diagnosis of KS remains difficult because based on the appreciation of facial features combined with other highly variable features. We describe a novel sign, namely the attenuation and/or congenital absence of the IPD crease of the third and fourth fingers associated with limitation of flexion of the corresponding joints, which seems to be specific of KS and could help the clinician to diagnose KS

Mise au point de techniques rapides de diagnostic prénatal de la trisomie 21

AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Deleterious mutations in exon 1 of MECP2 in Rett syndrome.

International audienceThe MECP2 gene is responsible for 80-85% of typical cases of Rett syndrome with deleterious mutations affecting exons 3 and 4. Recently, an alternate transcript including exon 1 was discovered with a new protein isoform (MeCP2_e1) much more abundant in brain. We screened exon 1 of MECP2 for mutations and for large rearrangements in a panel of 212 typical cases of Rett syndrome and one family case with atypical Rett syndrome. We identified two deleterious mutations (c.48_55dup and c.62+2_62+3del) and four large rearrangements encompassing exon 1 of MECP2. We also identified the c.16_21dup alteration formerly reported as c.3_4insGCCGCC and give additional support to classify this sequence variation as polymorphic. In our large panel of typical Rett, mutations affecting exon 1 of MECP2 represent 1% of the deleterious alleles. This study confirms that mutations in exon 1 of MECP2 are a rare cause of Rett syndrome

Not All Floating-Harbor Syndrome Cases are Due to Mutations in Exon 34 of SRCAP

International audienceFloating-Harbor syndrome (FHS) is a rare disorder characterized by short stature, delayed bone age, speech delay, and dysmorphic facial features. We report here the molecular analysis of nine cases, fulfilling the diagnostic criteria for FHS. Using exome sequencing, we identified SRCAP as the disease gene in two cases and subsequently found SRCAP truncating mutations in 6/9 cases. All mutations occurred de novo and were located in exon 34, in accordance with the recent report of Hood et al. However, the absence of SRCAP mutations in 3/9 cases supported genetic heterogeneity of FH syndrome. Importantly, no major clinical differences were observed supporting clinical homogeneity in this series of FHS patients. Hum Mutat 34:88-92, 2013. (C) 2012 Wiley Periodicals, Inc

Recurrent mutations in the CDKL5 gene: Genotype-phenotype relationships

Mutations in the cyclin-dependent kinase-like 5 gene (CDKL5) have been described in epileptic encephalopathies in females with infantile spasms with features that overlap with Rett syndrome. With more than 80 reported patients, the phenotype of CDKL5-related encephalopathy is well-defined. The main features consist of seizures starting before 6 months of age, severe intellectual disability with absent speech and hand stereotypies and deceleration of head growth, which resembles Rett syndrome. However, some clinical discrepancies suggested the influence of genetics and/or environmental factors. No genotype-phenotype correlation has been defined and thus there is a need to examine individual mutations. In this study, we analyzed eight recurrent CDKL5 mutations to test whether the clinical phenotype of patients with the same mutation is similar and whether patients with specific CDKL5 mutations have a milder phenotype than those with other CDKL5 mutations. Patients bearing missense mutations in the ATP binding site such as the p.Ala40Val mutation typically walked unaided, had normocephaly, better hand use ability, and less frequent refractory epilepsy when compared to girls with other CDKL5 mutations. In contrast, patients with mutations in the kinase domain (such as p.Arg59X, p.Arg134X, p.Arg178Trp/Pro/Gln, or c.145 + 2T > C) and frameshift mutations in the C-terminal region (such as c.2635_2636delCT) had a more severe phenotype with infantile spasms, refractory epileptic encephalopathy, absolute microcephaly, and inability to walk. It is important for clinicians to have this information when such patients are diagnosed. © 2012 Wiley Periodicals, Inc.status: publishe

Mecp2 deficiency disrupts norepinephrine and respiratory systems in mice.

Rett syndrome is a severe X-linked neurological disorder in which most patients have mutations in the methyl-CpG binding protein 2 (MECP2) gene and suffer from bioaminergic deficiencies and life-threatening breathing disturbances. We used in vivo plethysmography, in vitro electrophysiology, neuropharmacology, immunohistochemistry, and biochemistry to characterize the consequences of the MECP2 mutation on breathing in wild-type (wt) and Mecp2-deficient (Mecp2-/y) mice. At birth, Mecp2-/y mice showed normal breathing and a normal number of medullary neurons that express tyrosine hydroxylase (TH neurons). At approximately 1 month of age, most Mecp2-/y mice showed respiratory cycles of variable duration; meanwhile, their medulla contained a significantly reduced number of TH neurons and norepinephrine (NE) content, even in Mecp2-/y mice that showed a normal breathing pattern. Between 1 and 2 months of age, all unanesthetized Mecp2-/y mice showed breathing disturbances that worsened until fatal respiratory arrest at approximately 2 months of age. During their last week of life, Mecp2-/y mice had a slow and erratic breathing pattern with a highly variable cycle period and frequent apneas. In addition, their medulla had a drastically reduced number of TH neurons, NE content, and serotonin (5-HT) content. In vitro experiments using transverse brainstem slices of mice between 2 and 3 weeks of age revealed that the rhythm produced by the isolated respiratory network was irregular in Mecp2-/y mice but could be stabilized with exogenous NE. We hypothesize that breathing disturbances in Mecp2-/y mice, and probably Rett patients, originate in part from a deficiency in noradrenergic and serotonergic modulation of the medullary respiratory network

A French collaborative survey of 272 fetuses with 22q11.2 deletion: ultrasound findings, fetal autopsies and pregnancy outcomes

International audienceObjective: The 22q11.2 deletion (del22q11.2) is one of the most common microdeletions. We performed a collaborative, retrospective analysis in France of prenatal diagnoses and outcomes of fetuses carrying the del22q11.2.Methods: A total of 272 fetuses were included. Data on prenatal diagnosis, ultrasound findings, pathological features, outcomes and inheritance were analyzed.Results: The mean time of prenatal diagnosis was 25.6 ± 6 weeks of gestation. Most of the diagnoses (86.8%) were prompted by abnormal ultrasound findings [heart defects (HDs), in 83.8% of cases]. On fetal autopsy, HDs were again the most common disease feature, but thymus, kidney abnormalities and facial dysmorphism were also described. The deletion was inherited in 27% of cases. Termination of pregnancy (TOP) occurred in 68.9% of cases and did not appear to depend on the inheritance status. However, early diagnosis was associated with a higher TOP rate.Conclusion: This is the largest cohort of prenatal del22q11.2 diagnoses. As in postnatally diagnosed cases, HDs were the most frequently observed abnormalities. However, thymus and kidney abnormalities and polyhydramnios should also be screened for in the prenatal diagnosis of del22q11.2. Only the time of diagnosis appeared to be strongly associated with the pregnancy outcome: the earlier the diagnosis, the higher the TOP rate.© 2014 John Wiley & Sons, Ltd