De novo WNT5A-associated autosomal dominant Robinow syndrome suggests specificity of genotype and phenotype.

Robinow Syndrome (RS), a rare skeletal dysplasia syndrome, is characterized by dysmorphic features resembling a fetal face, mesomelic limb shortening, hypoplastic external genitalia in males, and renal and vertebral anomalies. Both autosomal dominant and autosomal recessive patterns of inheritance have been reported. Since the description of autosomal dominant Robinow Syndrome (ADRS; OMIM 180700) in 1969 by Meinhard Robinow and colleagues, the molecular etiology remained elusive until only recently. WNT5A was proposed to be the candidate gene for ADRS, as mutations were found in two affected families, one of those being the originally described index family. We report three families with RS caused by novel heterozygous WNT5A mutations, which were confirmed in the first family by whole exome sequencing, and in all by Sanger sequencing. To our knowledge, this is the largest number of published families with ADRS in whom a WNT5A mutation was identified. Families 1 and 2 are the first cases showing de novo inheritance in the affected family members and thus strengthen the evidence for WNT5A as the causative gene in ADRS. Finally, we propose WNT5A mutation specificity in ADRS, which may affect interactions with other proteins in the Wnt pathway.

X-linked congenital ptosis and associated intellectual disability, short stature, microcephaly, cleft palate, digital and genital abnormalities define novel Xq25q26 duplication syndrome.

Submicroscopic duplications along the long arm of the X-chromosome with known phenotypic consequences are relatively rare events. The clinical features resulting from such duplications are various, though they often include intellectual disability, microcephaly, short stature, hypotonia, hypogonadism and feeding difficulties. Female carriers are often phenotypically normal or show a similar but milder phenotype, as in most cases the X-chromosome harbouring the duplication is subject to inactivation. Xq28, which includes MECP2 is the major locus for submicroscopic X-chromosome duplications, whereas duplications in Xq25 and Xq26 have been reported in only a few cases. Using genome-wide array platforms we identified overlapping interstitial Xq25q26 duplications ranging from 0.2 to 4.76 Mb in eight unrelated families with in total five affected males and seven affected females. All affected males shared a common phenotype with intrauterine- and postnatal growth retardation and feeding difficulties in childhood. Three had microcephaly and two out of five suffered from epilepsy. In addition, three males had a distinct facial appearance with congenital bilateral ptosis and large protruding ears and two of them showed a cleft palate. The affected females had various clinical symptoms similar to that of the males with congenital bilateral ptosis in three families as most remarkable feature. Comparison of the gene content of the individual duplications with the respective phenotypes suggested three critical regions with candidate genes (AIFM1, RAB33A, GPC3 and IGSF1) for the common phenotypes, including candidate loci for congenital bilateral ptosis, small head circumference, short stature, genital and digital defects.

Anorectal malformations and pregnancy-related disorders: a registry-based case-control study in 17 European regions.

OBJECTIVE: To identify pregnancy-related risk factors for different manifestations of congenital anorectal malformations (ARMs). DESIGN: A population-based case-control study. SETTING: Seventeen EUROCAT (European Surveillance of Congenital Anomalies) registries, 1980-2008. POPULATION: The study population consisted of 1417 cases with ARM, including 648 cases of isolated ARM, 601 cases of ARM with additional congenital anomalies, and 168 cases of ARM-VACTERL (vertebral, anal, cardiac, tracheo-esophageal, renal, and limb defects), along with 13 371 controls with recognised syndromes or chromosomal abnormalities. METHODS: Multiple logistic regression analyses were used to calculate adjusted odds ratios (ORs) for potential risk factors for ARM, such as fertility treatment, multiple pregnancy, primiparity, maternal illnesses during pregnancy, and pregnancy-related complications. MAIN OUTCOME MEASURES: Adjusted ORs for pregnancy-related risk factors for ARM. RESULTS: The ARM cases were more likely to be firstborn than the controls (OR 1.6, 95% CI 1.4-1.8). Fertility treatment and being one of twins or triplets seemed to increase the risk of ARM in cases with additional congenital anomalies or VACTERL (ORs ranging from 1.6 to 2.5). Maternal fever during pregnancy and pre-eclampsia were only associated with ARM when additional congenital anomalies were present (OR 3.9, 95% CI 1.3-11.6; OR 3.4, 95% CI 1.6-7.1, respectively), whereas maternal epilepsy during pregnancy resulted in a five-fold elevated risk of all manifestations of ARM (OR 5.1, 95% CI 1.7-15.6). CONCLUSIONS: This large European study identified maternal epilepsy, fertility treatment, multiple pregnancy, primiparity, pre-eclampsia, and maternal fever during pregnancy as potential risk factors primarily for complex manifestations of ARM with additional congenital anomalies and VACTERL.

MLL2 mutation detection in 86 patients with Kabuki syndrome: a genotype-phenotype study.

Recently, pathogenic variants in the MLL2 gene were identified as the most common cause of Kabuki (Niikawa-Kuroki) syndrome (MIM#147920). To further elucidate the genotype-phenotype correlation, we studied a large cohort of 86 clinically defined patients with Kabuki syndrome (KS) for mutations in MLL2. All patients were assessed using a standardized phenotype list and all were scored using a newly developed clinical score list for KS (MLL2-Kabuki score 0-10). Sequencing of the full coding region and intron-exon boundaries of MLL2 identified a total of 45 likely pathogenic mutations (52%): 31 nonsense, 10 missense and four splice-site mutations, 34 of which were novel. In five additional patients, novel, i.e. non-dbSNP132 variants of clinically unknown relevance, were identified. Patients with likely pathogenic nonsense or missense MLL2 mutations were usually more severely affected (median 'MLL2-Kabuki score' of 6) as compared to the patients without MLL2 mutations (median 'MLL2-Kabuki score' of 5), a significant difference (p < 0.0014). Several typical facial features such as large dysplastic ears, arched eyebrows with sparse lateral third, blue sclerae, a flat nasal tip with a broad nasal root, and a thin upper and a full lower lip were observed more often in mutation positive patients.

Cytoplasmic localization of PML particles in laminopathies.

There is growing evidence that laminopathies, diseases associated with mutations in the LMNA gene, are caused by a combination of mechanical and gene regulatory distortions. Strikingly, there is a large variability in disease symptoms between individual patients carrying an identical LMNA mutation. This is why classical genetic screens for mutations appear to have limited predictive value for disease development. Recently, the widespread occurrence of repetitive nuclear ruptures has been described in fibroblast cultures from various laminopathy patients. Since this phenomenon was strongly correlated with disease severity, the identification of biomarkers that report on these rupture events could have diagnostic relevance. One such candidate marker is the PML nuclear body, a structure that is normally confined to the nuclear interior, but leaks out of the nucleus upon nuclear rupture. Here, we show that a variety of laminopathies shows the presence of these cytoplasmic PML particles (PML CPs), and that the amount of these protein aggregates increases with severity of the disease. In addition, between clinically healthy individuals, carrying LMNA mutations, significant differences can be found. Therefore, we postulate that detection of PML CPs in patient fibroblasts could become a valuable marker for diagnosis of disease development.

Novel and recurrent TRPV4 mutations and their association with distinct phenotypes within the TRPV4 dysplasia family.

BACKGROUND: Mutations in TRPV4, a gene that encodes a Ca(2+) permeable non-selective cation channel, have recently been found in a spectrum of skeletal dysplasias that includes brachyolmia, spondylometaphyseal dysplasia, Kozlowski type (SMDK) and metatropic dysplasia (MD). Only a total of seven missense mutations were detected, however. The full spectrum of TRPV4 mutations and their phenotypes remained unclear. OBJECTIVES AND METHODS: To examine TRPV4 mutation spectrum and phenotype-genotype association, we searched for TRPV4 mutations by PCR-direct sequencing from genomic DNA in 22 MD and 20 SMDK probands. RESULTS: TRPV4 mutations were found in all but one MD subject. In total, 19 different heterozygous mutations were identified in 41 subjects; two were recurrent and 17 were novel. In MD, a recurrent P799L mutation was identified in nine subjects, as well as 10 novel mutations including F471del, the first deletion mutation of TRPV4. In SMDK, a recurrent R594H mutation was identified in 12 subjects and seven novel mutations. An association between the position of mutations and the disease phenotype was also observed. Thus, P799 in exon 15 is a hot codon for MD mutations, as four different amino acid substitutions have been observed at this codon; while R594 in exon 11 is a hotspot for SMDK mutations. CONCLUSION: The TRPV4 mutation spectrum in MD and SMDK, which showed genotype-phenotype correlation and potential functional significance of mutations that are non-randomly distributed over the gene, was presented in this study. The results would help diagnostic laboratories establish efficient screening strategies for genetic diagnosis of the TRPV4 dysplasia family diseases.

Sixteen New Cases Contributing to the Characterization of Patients with Distal 22q11.2 Microduplications.

The chromosome region 22q11.2 has long been recognized to be susceptible to genomic rearrangement. More recently, this genomic instability has been shown to extend distally (involving LCR22E-H) to the commonly deleted/duplicated region. To date, 21 index cases with 'distal' 22q11.2 duplications have been reported. We report on the clinical and molecular characterization of 16 individuals with distal 22q11.2 duplications identified by DNA microarray analysis. Two of the individuals have been partly described previously. The clinical phenotype varied among the patients in this study, although the majority displayed various degrees of developmental delay and speech disturbances. Other clinical features included behavioral problems, hypotonia, and dysmorphic facial features. Notably, none of the patients was diagnosed with a congenital heart defect. We found a high degree of inherited duplications. Additional copy number changes of unclear clinical significance were identified in 5 of our patients, and it is possible that these may contribute to the phenotypic expression in these patients as has been suggested recently in a 2-hit 'digenic' model for 16p12.1 deletions. The varied phenotypic expression and incomplete penetrance observed for distal 22q11.2 duplications makes it exceedingly difficult to ascribe pathogenicity for these duplications. Given the observed enrichment of the duplication in patient samples versus healthy controls, it is likely that distal 22q11.2 duplications represent a susceptibility/risk locus for speech and mild developmental delay.

Sanfilippo B in an elderly female psychiatric patient: a rare but relevant diagnosis in presenile dementia.

OBJECTIVE: Sanfilippo B is a rare autosomal recessive mucopolysaccharidosis (MPS IIIB) caused by a deficiency of N-acetyl-alpha-D-glucosaminidase (NAGLU). METHOD: A mild mentally retarded elderly female patient is described with a slowly progressive dementia who had given birth to a daughter who developed normally. RESULTS: Metabolic screening revealed an enhanced concentration of heparan sulfate in urine. Enzymatic assay demonstrated deficiency of N-acetyl-alpha-D-glucosaminidase. Mutations in the NAGLU gene were found. One mentally retarded and hospitalized elder brother was also found to have MPS IIIB, whereas a second brother, who had died earlier, is suspected to have had the same metabolic disorder. Prior to the development of dementia, both the patient and her brother showed autistic like features, signs of ideomotor apraxia and weakness in verbal comprehension. CONCLUSION: Screening for metabolic disorders, in particular MPSes, should always be considered in patients with a history of mental deficit and dementia or progressive functional decline.

A Feingold syndrome case with previously undescribed features and a new mutation.

Feingold syndrome (FS) is a dominantly inherited combination of microcephaly with or without learning disabilities, hand and foot abnormalities, short palpebral fissures and esophageal/duodenal atresia. The syndrome has autosomal dominant inheritance with full penetrance, and variable expressivity. Digital anomalies are almost always present. The gene for FS is localized to a 2.2 cM region in 2p23-p24. We report on the first Turkish family with Feingold syndrome. The propositus is a male infant with microcephaly, frontal balding, brachymesophalangy of the second and fifth fingers, bilateral syndactyly of toes 2-3, facial anomalies, choanal atresia and focal epilepsy. His father has microcephaly, and more severe hands and feet abnormalities. One of his brothers died because of eosofageal atresia. Clinical presentation of the family was suggestive of Feingold syndrome, and genetic testing of the MYCN gene confirmed the diagnosis. The missense mutation we report here has not been described previously. FS is an autosomal dominant condition, and therefore, the diagnosis has important implications for genetic counseling.

An 8.35 Mb overlapping interstitial deletion of 8q24 in two patients with coloboma, congenital heart defect, limb abnormalities, psychomotor retardation and convulsions.

Chromosome analysis in two young patients with multiple congenital anomalies revealed a de novo interstitial deletion of 8q that has not been reported before. The deletions were overlapping by 8.35 Mb (8q24.21q24.23). The clinical features shared by our patients were coloboma, VSD, digital abnormalities, congenital dislocation of a hip, feeding problems, psychomotor delay and convulsions. The deletion included the region for Langer-Giedion syndrome (TRPS1 and EXT1) in the girl only. However, she is too young to present features of this syndrome, apart from dysmorphic features like a bulbous nose and notched alae nasi. Several genes are present in the commonly deleted region, including genes with unknown function, and genes for which haploinsufficiency is known to have no phenotypic effect in mice (Wnt1). A gene that might play a role in the convulsions of our patients is KCNQ3.

Clinical and molecular characteristics of 1qter microdeletion syndrome: delineating a critical region for corpus callosum agenesis/hypogenesis.

BACKGROUND: Patients with a microscopically visible deletion of the distal part of the long arm of chromosome 1 have a recognisable phenotype, including mental retardation, microcephaly, growth retardation, a distinct facial appearance and various midline defects including corpus callosum abnormalities, cardiac, gastro-oesophageal and urogenital defects, as well as various central nervous system anomalies. Patients with a submicroscopic, subtelomeric 1qter deletion have a similar phenotype, suggesting that the main phenotype of these patients is caused by haploinsufficiency of genes in this region. OBJECTIVE: To describe the clinical presentation of 13 new patients with a submicroscopic deletion of 1q43q44, of which nine were interstitial, and to report on the molecular characterisation of the deletion size. RESULTS AND CONCLUSIONS: The clinical presentation of these patients has clear similarities with previously reported cases with a terminal 1q deletion. Corpus callosum abnormalities were present in 10 of our patients. The AKT3 gene has been reported as an important candidate gene causing this abnormality. However, through detailed molecular analysis of the deletion sizes in our patient cohort, we were able to delineate the critical region for corpus callosum abnormalities to a 360 kb genomic segment which contains four possible candidate genes, but excluding the AKT3 gene.

[Congenital long QT-syndrome: the cause of recurrent syncope and sudden death at a young age]. / Congenitaal lange-QT-tijdsyndroom: oorzaak van recidiverende wegrakingen en plotse dood op jonge leeftijd.

Congenital long QT-syndrome (LQTS) was diagnosed in three patients. The first patient, a 10-year-old girl, presented with recurrent episodes of syncope during swimming and was diagnosed with type 1 LQTS. The second patient, a 36-year-old asymptomatic man, was accidentally diagnosed with type 2 LQTS. His family history revealed syncope and sudden death at a young age after auditory stimuli. Type 3 LQTS was diagnosed post-mortem in a 16-year-old boy who died during his sleep. All clinical diagnoses were confirmed by genetic testing. Congenital LQTS is one of the leading causes of sudden cardiac death at a young age. Mutations in genes encoding for myocardial ion channel proteins lead to a prolonged QT-interval and abnormal ST-T segments in the 12-lead ECG. Patients may present with syncope or sudden cardiac death caused by ventricular tachyarrhythmias. Genotype-specific differences in ECG-abnormalities and triggers for cardiac events may help to distinguish the type of LQTS and make possible the initiation of genotype-specific treatment before the results of genetic testing are known. Identification of the genetic substrate by genetic testing, genotype-specific treatment, and the possibility of treatment with an implantable cardioverter-defibrillator have all led to dramatic improvement in the prognosis of patients with LQTS. Therefore, young patients with unexplained recurrent syncope after specific stimuli and those with atypical forms of epilepsy should be referred for cardiologic evaluation in a specialised centre.

A single hERG mutation underlying a spectrum of acquired and congenital long QT syndrome phenotypes.

The long QT syndrome (LQTS) is a multi-factorial disorder that predisposes to life-threatening arrhythmias. Both hereditary and acquired subforms have been identified. Here, we present clinical and biophysical evidence that the hERG mutation c.1039 C>T (p.Pro347Ser or P347S) is responsible for both the acquired and the congenital phenotype. In one case the genotype remained silent for years until the administration of several QT-prolonging drugs resulted into a full-blown phenotype, that was reversible upon cessation of these compounds. On the other hand the mutation was responsible for a symptomatic congenital LQTS in a Dutch family, displaying a substantial heterogeneity of the clinical symptoms. Biophysical characterization of the p.Pro347Ser potassium channels using whole-cell patch clamp experiments revealed a novel pathogenic mechanism of reciprocal changes in the inactivation kinetics combined with a dominant-negative reduction of the functional expression in the heterozygous situation, yielding a modest genetic predisposition for LQTS. Our data show that in the context of the multi-factorial aetiology underlying LQTS a modest reduction of the repolarizing power can give rise to a spectrum of phenotypes originating from one mutation. This observation increases the complexity of genotype-phenotype correlations in more lenient manifestations of the disease and underscores the difficulty of predicting the expressivity of the LQTS especially for mutations with a more subtle impact such as p.Pro347Ser.

Complex chromosome 17p rearrangements associated with low-copy repeats in two patients with congenital anomalies.

Recent molecular cytogenetic data have shown that the constitution of complex chromosome rearrangements (CCRs) may be more complicated than previously thought. The complicated nature of these rearrangements challenges the accurate delineation of the chromosomal breakpoints and mechanisms involved. Here, we report a molecular cytogenetic analysis of two patients with congenital anomalies and unbalanced de novo CCRs involving chromosome 17p using high-resolution array-based comparative genomic hybridization (array CGH) and fluorescent in situ hybridization (FISH). In the first patient, a 4-month-old boy with developmental delay, hypotonia, growth retardation, coronal synostosis, mild hypertelorism, and bilateral club feet, we found a duplication of the Charcot-Marie-Tooth disease type 1A and Smith-Magenis syndrome (SMS) chromosome regions, inverted insertion of the Miller-Dieker lissencephaly syndrome region into the SMS region, and two microdeletions including a terminal deletion of 17p. The latter, together with a duplication of 21q22.3-qter detected by array CGH, are likely the unbalanced product of a translocation t(17;21)(p13.3;q22.3). In the second patient, an 8-year-old girl with mental retardation, short stature, microcephaly and mild dysmorphic features, we identified four submicroscopic interspersed 17p duplications. All 17 breakpoints were examined in detail by FISH analysis. We found that four of the breakpoints mapped within known low-copy repeats (LCRs), including LCR17pA, middle SMS-REP/LCR17pB block, and LCR17pC. Our findings suggest that the LCR burden in proximal 17p may have stimulated the formation of these CCRs and, thus, that genome architectural features such as LCRs may have been instrumental in the generation of these CCRs.

Anaerobic desulphurisation of thiophenes by mixed microbial communities from oilfields.

Anaerobic enrichment cultures obtained from oil fields degraded various thiophenic compounds i.e. thiophene, benzothiophene and dibenzothiophene, with the concomitant formation of sulphide using hydrogen, lactate and ethanol as possible electron donors. It was demonstrated that dibenzothiophene was converted to biphenyl. However, hydrocarbon products from benzothiophene and thiophene desulphurisation could not be detected. After further enrichment on thiophenic compounds as the sole electron acceptor, the conversion activity disappeared while homo-acetogenic bacteria became abundantly present. In order to gain stable conversions of thiophenic compounds, attempts were made to isolate the sulphide-producing bacteria. Two highly enriched cultures were obtained, which degraded thiophenic compounds, but the activity remained low and homo-acetogenesis remained dominant.

[Hypertrophic cardiomyopathy: from diagnosis to prevention]. / Hypertrofische cardiomyopathie: van diagnostiek naar preventie.

In a 55-year-old man, his two sons aged 32 and 30 years and a 3-year-old grandchild, a gene mutation related to an increased chance of hypertrophic cardiomyopathy was found. The adults had complaints of cardiac arrhythmias varying from dizziness to cardiac arrest and received medication; a defibrillator was also implanted in the case of the sons. Familial hypertrophic cardiomyopathy can be diagnosed in an early stage with DNA screening methods. At that time 'patients' (carriers) often do not exhibit symptoms. This offers the possibility of taking therapeutic measures to prevent or slow down the disease process. However, the scientific basis for preventive therapy is inadequate, so that medical-ethical dilemmas arise which can affect the decision-making process with respect to genetic testing. Additional research must lead to satisfactory preventive therapies, so that in the future the genetic diagnosis 'hypertrophic cardiomyopathy' can be effectively translated into disease prevention.

Wolf-Hirschhorn (4P-) syndrome in adults.

Wolf-Hirschhorn syndrome (WHS) or 4p-deletion syndrome has been extensively described in children. Knowledge on adult WHS patients is still limited due to the small number of published cases. We present 4 adults and review the literature. The phenotype of adult WHS is in general similar to that of childhood WHS. Growth retardation, microcephaly and mental retardation are the rule in both adults and children. Facial dysmorphism also remains similar. The main difference lies in the absence of serious internal (cardiac) abnormalities in adult WHS. Mental retardation ranges from moderate to severe. The nosological overlap between WHS and Pitt-Rogers-Danks syndrome (PRDS) is discussed. More extensive data on adult WHS are needed for appropriate counselling of families with affected young children.