Detection of 15 novel mutations in 52 children from 40 families with the Marfan or Loeys-Dietz syndrome and phenotype-genotype correlations.

We report about 52 pediatric patients of 40 different families with confirmed Marfan syndrome (MFS) in 49 patients and Loeys-Dietz syndrome (LDS) in 3 patients. We found 39 different mutations, 15 of them being novel. Phenotype-genotype correlation in the 49 MFS patients showed that the majority of patients carrying mutations in exons 1-21 had ectopic lens (80%). Patients having mutations in exons 23-32 had a higher probability of aortic root dilation, in 50% even above a z score of 3. We found three children with neonatal MFS form, two of them with novel mutations. Of the three LDS patients, only one presented with the typical phenotype of LDS type 1.

[Hip dysplasia and spinal osteochondritis (Scheuermann's disease) in a girl with type II manifesting collagenopathy]. / Hüftdysplasie und Morbus Scheuermann bei einem Mädchen mit Typ-II-Kollagenopathie.

OBJECTIVES: This paper describes the natural course of irritable hip pain associated with spinal rigidity and pain in the thoracic region with subsequent development of mild kyphosis in a girl with a mutation in the collagen 2 alpha 1 gene (type II collagenopathy). METHODS: Phenotypic and genotypic characterization was carried out in a 14-year-old girl to identify the underlying pathology of severe irritable hip pain associated with thoracic spinal rigidity and pain. Detailed clinical examination, skeletal survey and genetic testing were performed accordingly. Bernese periacetabular osteotomy was used to alleviate pain and to improve the anatomical correlation of the acetabular and femoral heads. RESULTS: Short stature associated with acetabulo-femoral dysplasia, spinal osteochondritis (Scheuermann's disease) and mild thoracic kyphosis were the most prominent abnormalities. Genetic analysis showed a heterozygous mutation in the collagen type II gene (COL2A1-c.1636G>A, p. G546S). A Bernese periacetabular osteotomy was performed to improve the clinical status of the patient. There was significant improvement in the extrusion index, the acetabular index and the lateral center-edge angle. CONCLUSIONS: Hip dysplasia and Scheuermann's osteochondritis have never been reported in connection with a mutation in COL2A1 (collagenopathy type II). Awareness is needed for careful phenotypic and genotypic characterization in patients with irritable hip pain and spinal stiffness.

MeCP2 mutant protein is expressed in astrocytes as well as in neurons and localizes in the nucleus.

The MECP2 gene, located at Xq28, encodes methyl-CpG-binding protein 2 (MeCP2), which is frequently mutated (up to 90%) in Rett syndrome (RTT). RTT is a progressive neurodevelopmental disorder, which affects primarily girls during early childhood and it is one of the most common causes of mental retardation in females. R270X is one of the most frequent recurrent MECP2 mutations among RTT cohorts. The R270X mutation resides within the TRD-NLS (Transcription Repression Domain-Nuclear Localization Signal) region of MeCP2 and causes a more severe clinical phenotype with increased mortality as compared to other mutations. To evaluate the functional role of the R270X mutation, we generated a transgenic mouse model expressing MeCP2(270_EGFP) (human mutation equivalent) by BAC recombineering. The expression pattern of MeCP2(270_EGFP) was similar to that of endogenous MeCP2. Strikingly, MeCP2(270_EGFP) localizes in the nucleus, contrary to the conjecture that R270X could cause disruption of the NLS. In primary hippocampal cells, we show that MeCP2(270_EGFP) was expressed in astrocytes by colocalization with the astrocyte-specific marker glial fibrillary acidic protein. Our data showing expression of MeCP2(270_EGFP) in transgenic mice astrocytes further reinforce the recent findings concerning the expression of MeCP2 in the glial cells.

Leupaxin acts as a mediator in prostate carcinoma progression through deregulation of p120catenin expression.

Recently, we could show that the focal adhesion protein leupaxin (LPXN) is expressed in human prostate carcinomas (PCa) and induces invasiveness of androgen-independent PCa cells. In this study we show that LPXN enhanced the progression of existing PCa in vivo by breeding transgenic mice with prostate-specific LPXN expression and TRAMP mice (transgenic adenocarcinoma of mouse prostate). Double transgenic LPXN/TRAMP mice showed a significant increase in poorly differentiated PCa and distant metastases as compared with control TRAMP mice. Additional studies on primary PCa cells generated from both transgenic backgrounds confirmed the connection regarding LPXN overexpression and increased motility and invasiveness of PCa cells. One mediator of LPXN-induced invasion was found to be the cell-cell adhesion protein p120catenin (p120CTN). Both in vitro and in vivo experiments revealed that p120CTN expression negatively correlates with LPXN expression, followed by a redistribution of beta-catenin. Downregulation of LPXN using small interfering RNAs (siRNAs) resulted in a membranous localization of beta-catenin, whereas strong nuclear accumulation of beta-catenin was observed in p120CTN knockdown cells leading to enhanced transcription of the beta-catenin target gene matrix metalloprotease-7. In conclusion, the present results indicate that LPXN enhances the progression of PCa through downregulation of p120CTN expression and that LPXN could function as a marker for aggressive PCa in the future.

Dysmorphic syndrome of hereditary neuralgic amyotrophy associated with a SEPT9 gene mutation--a family study.

We report a family in which two siblings presented with an apparent dysmorphic syndrome, including hypotelorism, blepharophimosis, slight ptosis, epicanthal folds, microstomia and dysmorphic ears. One sibling had a cleft palate. Initially, blepharophimosis, ptosis, and epicanthus inversus syndrome (BPES) was suspected; however, mutation of the FOXL2 gene was not detected. Moreover, the patients' father and paternal grandmother had experienced recurrent episodes of unilateral brachial neuritis and were diagnosed to have hereditary neuralgic amyotrophy (HNA). HNA is a rare, inherited form of brachial neuritis whose phenotypic spectrum may include hypotelorism, cleft palate and other minor dysmorphisms. HNA maps to chromosome 17q25 and is associated with mutations in the SEPT9 gene. After confirming a heterozygous SEPT9 mutation (R88W) in the father and his mother, it became apparent that the dysmorphic features in the children were part of HNA and that previous complaints of the daughter, erroneously diagnosed as pronatio dolorosa and then epiphysiolysis of the capitellum humeri, were in fact a first neuralgic pain attack. Both children were shown to have inherited the paternal SEPT9 mutation. Wider recognition of HNA as a syndromic disorder may facilitate its diagnosis in affected young persons who may not yet have manifested episodes of brachial neuritis.

Folate receptor autoantibodies and spinal fluid 5-methyltetrahydrofolate deficiency in Rett syndrome.

Rett syndrome was associated with low cerebrospinal fluid (CSF) 5-methyltetrahydrofolate (5MTHF) in 42-50% of European patients whereas approximately 93% of the patients from North-America had a normal CSF 5MTHF status. We determined the CSF folate status in Rett patients living in North- and South-Western Europe and measured serum folate receptor (FR) autoantibodies of the blocking type to explain the reduced folate transport across the choroid plexus. Irrespective of their MECP2 genotype and despite normal plasma folate values, 14 of 33 Rett patients (42%) had low CSF folate levels. Blocking FR autoantibodies were found in 8 of the Rett patients (24%), 6 of whom had low CSF folate levels. FR autoimmunity was primarily found within the group of Rett patients with low CSF folate status with a higher incidence in North-Western Europe. In Rett patients from North-America 74 of 76 girls had higher folate values in both serum and CSF than European patients. The food folate fortification in North-America may account for the higher folate levels and may prevent CFD in these Rett patients. FR autoimmunity occurred predominantly in Rett patients from North-Western Europe and may contribute to cerebral folate deficiency (CFD).

Very mild cases of Rett syndrome with skewed X inactivation.

BACKGROUND: Rett syndrome, a common cause of mental retardation in females, is caused by mutations in the MECP2 gene. Most females with MECP2 mutations fulfil the established clinical criteria for Rett syndrome, but single cases of asymptomatic carriers have been described. It is therefore likely that there are individuals falling between these two extreme phenotypes. OBJECTIVE: To describe three patients showing only minor symptoms of Rett syndrome. FINDINGS: The patient with the best intellectual ability had predominantly psychiatric problems with episodes of uncontrolled aggression that have not been described previously in individuals with MECP2 mutations. All three patients had normal hand function, communicated well, and showed short spells of hyperventilation only under stress. Diagnosis in such individuals requires the identification of subtle signs of Rett syndrome in girls with a mild mental handicap. Analysis of the MECP2 gene revealed mutations that are often found in classical Rett syndrome. Skewed X inactivation was present in all three cases, which may explain the mild phenotype. CONCLUSIONS: Because of skewed X inactivation, the phenotype of Rett patients may be very mild and hardly recognisable.

Prenatal diagnosis of a large de novo terminal deletion of chromosome 11q.

OBJECTIVE: To describe the prenatal phenotype of the 11q deletion syndrome (Jacobsen syndrome) and present the molecular characterization of the deletion in the case presented. CASE: Ultrasound at 18 and 20 weeks of gestation, on a 34-year-old woman who presented for amniocentesis, revealed slow movements, oligohydramnios and dilatation of the cerebral ventricles in the fetus. Maternal and paternal ages were 34 and 38 years, respectively. RESULTS: Prenatal karyotyping of cultured amniotic fluid cells revealed an 11q terminal deletion, 46,XX,del(11)(q23) (Jacobsen syndrome). Real-time quantitative PCR analysis was used to identify and map the breakpoint physically to a 45-kb region located 14.5 Mb from the 11q telomere. Polymorphic DNA marker analysis showed that DNA sequences on the paternally derived chromosome are deleted. At autopsy, facial dysmorphism without major malformations was recorded. Examination of the internal organs disclosed the following abnormalities: a Meckels' diverticulum of 4-mm length, adhesion between the gall bladder and the transverse colon, and bilaterally bilobed lungs without further situs anomalies. CONCLUSION: Our case demonstrates significant phenotypic variability of Jacobsen syndrome at midtrimester pregnancy; the syndrome may be manifested at this stage only by mild to moderate ventriculomegaly of the brain.

Association of Jacobsen syndrome and bipolar affective disorder in a patient with a de novo 11q terminal deletion.

We report on a young woman with Jacobsen syndrome (JBS) who was admitted to our psychiatric department because of a bipolar affective disorder (BPAD). Chromosome analysis was performed due to the fact that she had mental retardation, short stature, and subtle facial anomalies. A deletion of the distal long arm of chromosome 11 was found. A detailed mapping of the deletion breakpoint by quantitative real time PCR revealed a true terminal 11q deletion of approximately 8 Mb corresponding to the karyotype 46,XX,del(11)(q24.2). Polymorphic DNA marker analysis showed that the deletion is located on the paternal chromosome. Additionally, laboratory investigations revealed a low platelet count and magnetic resonance imaging of the brain showed white matter T2 hyperintensities in frontotemporal regions, which are unlikely to result from a demyelinating process as indicated by localized proton magnetic resonance spectroscopy. To our knowledge, this is the first report describing a BPAD in a case with JBS.

Gross rearrangements of the MECP2 gene are found in both classical and atypical Rett syndrome patients.

MECP2 mutations are identifiable in approximately 80% of classic Rett syndrome (RTT), but less frequently in atypical RTT. We recruited 110 patients who fulfilled the diagnostic criteria for Rett syndrome and were referred to Cardiff for molecular analysis, but in whom an MECP2 mutation was not identifiable. Dosage analysis of MECP2 was carried out using multiplex ligation dependent probe amplification or quantitative fluorescent PCR. Large deletions were identified in 37.8% (14/37) of classic and 7.5% (4/53) of atypical RTT patients. Most large deletions contained a breakpoint in the deletion prone region of exon 4. The clinical phenotype was ascertained in all 18 of the deleted cases and in four further cases with large deletions identified in Goettingen. Five patients with large deletions had additional congenital anomalies, which was significantly more than in RTT patients with other MECP2 mutations (2/193; p<0.0001). Quantitative analysis should be included in molecular diagnostic strategies in both classic and atypical RTT.

Fetal alcohol syndrome in association with Rett syndrome.

Fetal alcohol syndrome in association with RETT syndrome: We report on a girl with neonatal dystrophy, microcephaly, heart defect, and the characteristic features of alcohol embryopathy. Later, she developed distinctive features of RETT syndrome including loss of early acquired developmental skills and presented typical symptoms of RETT syndrome as reduction of communication skills, reduction of hand function, hyperventilation, and grinding of teeth. Molecular analysis of the MECP2 gene revealed the c.808T>C (R270X) mutation located in the nuclear localisation signal sequence of the gene. Our report highlights the importance of considering the diagnosis of RETT syndrome even in patients who are already suffering from a defined disease.

Identification and characterization of murine Brunol4, a new member of the elav/bruno family.

RNA-binding proteins are involved in post-transcriptional processes like mRNA stabilization, post-transcriptional modification, and transport and have been suggested to play an important role in developmental gene regulation. We report here the cloning and characterization of Brunol4, a novel mouse cDNA closely related to the elav-type family of genes encoding for RNA-binding proteins and a subfamily recently named after the bruno gene of Drosophila. Murine Brunol4 is localized near the centromere of chromosome 18. The cDNA sequence of Brunol4 is separated by 12 introns and the size of Brunol4 may be around 250 kb due to the large size of several introns. Brunol4 expression is detectable in the developing embryo and, later on becomes mainly restricted to cerebral structures, in particular the cerebellum where it persists in the adult organism. We predict a role of Brunol4 and the respective human homologue in differentiation and maintenance of neuronal structures.

Influence of mutation type and location on phenotype in 123 patients with Rett syndrome.

Rett syndrome (RTT) is a neurodevelopmental disorder that almost exclusively affects girls. It is caused by mutations in the MECP2 gene that encodes the methyl-CpG-binding protein 2 (MeCP2). In this study we correlated mutation type and location with the severity of the phenotype in 123 girls with RTT. The ability to sit, walk, speak, hand function, head growth, occurrence of epilepsy and a combined severity score were assessed in all girls at 5 years of age and then statistically correlated with the results of the molecular genetic tests. We found that patients who carry either missense mutations or deletions located within the hotspot for deletions, an area between the base pairs (bp) 1030 and 1207 of the MECP2 gene, present with a milder phenotype than other patients. We correlated the location of the mutations with the phenotype and found that all mutations that lead to either a complete or partial truncation of the region coding for the nuclear localisation signal (NLS) are associated with a more severe phenotype than other truncating mutations (p = 0.001). We did not find a significant difference between the patients with mutations in the methyl-CpG-binding domain (MBD) and those with mutations in the transcriptional repression domain (TRD). We conclude that mutation type and location correlate with the phenotype in Rett syndrome. All mutations that impair the nuclear localisation signal (NLS) are associated with more severe phenotypes.

Altered methylation pattern of the G6 PD promoter in Rett syndrome.

Rett syndrome (RTT) is a neurodevelopmental disorder that almost exclusively affects girls. Recently mutations in MECP2, that encodes the methyl CpG binding protein 2 (MeCP2), have been found to cause RTT. MeCP2 has a role in gene silencing. It binds to methylated cytosine in the DNA and recruits histone deacetylases. We studied the methylation pattern of the promoters of two X chromosomal genes, G6 PD and SYBL1, in patients with RTT and in a control group. Both genes undergo X inactivation which correlates with promoter methylation. A 1 : 1 ratio of methylated versus non-methylated alleles was expected. In the control group a median ratio of 47 : 53 of methylated to non-methylated alleles was found at the G6 PD promoter locus. In 22 patients with RTT the median ratio was significantly different, 33 : 67 (p < 0.0001). Analysis of the SYBL1 promoter revealed an almost identical median ratio of methylated versus non-methylated alleles (RTT 47 : 53; control 49 : 51), however, the range was wider in the RTT group (RTT 23 : 77 to 56 : 44; control 43 : 57 to 55 : 45). There was no apparent correlation between G6 PD promoter methylation status and mutations in the MeCP2 gene or the severity of the clinical phenotype in our patient group. The finding of reduced methylation at the G6 PD promoter is an interesting finding and suggests that there could be widespread dysregulation of X chromosomal genes in Rett syndrome.

Identification of the human ortholog of the t-complex-encoded protein TCTE3 and evaluation as a candidate gene for primary ciliary dyskinesia.

Primary ciliary dyskinesia (PCD) is a heterogeneous autosomal recessive disease that is caused by impaired ciliary and flagellar functions. About 50% of PCD patients show situs inversus, denoted as Kartagener syndrome. In most cases, axonemal defects in cilia and sperm tails can be demonstrated by electron microscopy, i.e. PCD patients often lack inner and/or outer dynein arms in their sperm tails and cilia, supporting the hypothesis that mutations in dynein genes may cause PCD. In order to identify novel PCD genes we have isolated the human ortholog of the murine TCTE3 gene. The human TCTE3 gene encodes a dynein light chain and shares high similarity to dynein light chains of other species. The TCTE3 gene is expressed in tissues containing cilia or flagella, it is composed of four exons and located on chromosome 6q25-->q27. To elucidate the role of TCTE3 as a candidate gene for PCD a mutational analysis of thirty-six PCD patients was performed. We detected five polymorphisms in the coding sequence and in the 5' UTR of the TCTE3 gene. In one patient a heterozygous nucleotide exchange was identified resulting in an arginine to isoleucine substitution at the amino acid level. However, this exchange was also detected in one control DNA. Our results indicate that mutations in the TCTE3 gene are not a main cause of primary ciliary dyskinesia.