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Summary The phenotypic variation of Klinefelter syndrome (KS) is wide and may by caused by various genetic and epigenetic effects. Skewed inactivation of the supra-numerical X chromosome and polymorphism in the androgen receptor ( AR) have been suggested as plausible causes. We wanted to describe X-chromosome inactivation patterns and the AR polymorphism and correlate these to clinical findings in KS in a cross-sectional study. To that end, we studied 70 KS patients enrolled from fertility clinics and endocrine clinics and 70 age-matched control subjects. The main outcome was X-chromosome inactivation pattern (skewX), AR polymorphism (CAGn - repeat length) and correlation to anthropometrical, hormonal, metabolic and bone-related variables. Forty-six of 70 KS men were heterozygous for CAGn. The shortest and the longest alleles were equally frequent inactivated and the mean CAGn of the two alleles did not differ significantly from the CAGn from either KS men, homozygous for the CAGn, or from the control subjects (22 vs. 23 vs. 21). SkewX was found in 12 of the 46 informative KS men (26%). In KS, height and arm span correlated positively to CAGn, whereas total cholesterol and haematocrit correlated negatively to CAGn. In controls, bone mineral density at the spine and hip correlated positively with CAGn, whereas adiponectin correlated negatively with CAGn. SkewX did not correlate to any of the investigated parameters. We conclude that CAGn polymorphism in AR explain some of the phenotypic variation in KS, whereas skewed X-chromosome inactivation did not. The impact of CAGn on final height may be caused by later reactivation of the pituitary-gonadal axis. [ABSTRACT FROM AUTHOR]

The X-linked form of Alport syndrome (AS) is caused by mutations in the COL4A5 gene encoding the α5 chain of type IV collagen. Most COL4A5 mutations are individual, and mutation analysis is complicated by the size of the gene and the number of exons. Larger structural rearrangements account for 10–15% of mutations. We have established a method for mutation analysis of COL4A5 based on reverse transcriptase-polymerase chain reaction analysis of mRNA from cultured skin fibroblasts and multiplex ligation-dependent probe amplification (MLPA) on genomic DNA. One advantage of using skin biopsies for the mRNA analysis is the possibility of immunohistochemical staining for the α5(IV) chain on skin sections to support a diagnosis of X-linked AS. A mutation was detected in all five cases included. One patient presenting with AS and diffuse leiomyomatosis was found to have a COL4A5 deletion extending into and comprising COL4A6 exons 1, 1′, and 2. We have evaluated the MLPA assay on samples from 67 previously tested AS patients (45 males and 22 females) and 20 controls. We found that the combination of cDNA and MLPA analysis improves the mutation detection rate in COL4A5 and that MLPA should be the first step in genetic testing for X-linked AS. [ABSTRACT FROM AUTHOR]

Autosomal recessive Parkinson's disease (PD) with early-onset may be caused by mutations in the parkin gene ( PARK2). We have ascertained 87 Danish patients with an early-onset form of PD (age at onset ≤40 years, or ≤50 years if family history is positive) in a multicenter study in order to determine the frequency of PARK2 mutations. Analysis of the GTP cyclohydrolase I gene ( GCH1) and the tyrosine hydroxylase gene ( TH), mutated in dopa-responsive dystonia and juvenile PD, have also been included. Ten different PARK2 mutations were identified in 10 patients. Two of the patients (2.3%) were found to have homozygous or compound heterozygous mutations, and eight of the patients (9.2%) were found to be heterozygous. A mutation has been identified in 10.4% of the sporadic cases and in 15.0% of cases with a positive family history of PD. One patient was found to be heterozygous for both a PARK2 mutation and a missense mutation (A6T) in TH of unknown significance. It cannot be excluded that both mutations contribute to the phenotype. No other putative disease causing TH or GCH1 mutations were found. In conclusion, homozygous, or compound heterozygous PARK2 mutations, and mutations in GCH1 and TH, are rare even in a population of PD patients with early-onset of the disease. [ABSTRACT FROM AUTHOR]

Background and Objectives The aim of this study was to investigate whether inflammation and regeneration are prominent in mildly affected muscles of patients with facioscapulohumeral muscular dystrophy type 1A ( FSHD1A). Inflammation in muscle has been suggested by MRI studies in patients with FSHD1A. Methods We analysed immunohistological and histological stains of muscle biopsies from 24 patients with FSHD1A, using 10 patients with Becker muscular dystrophy ( BMD) for comparison. Results Internalized nuclei were more prevalent in BMD (23.7 ± 10.8%) vs FSHD1A (6.3 ± 6.8%; P < 0.001), indicating more past regenerating fibres in BMD. Recently regenerating fibres, expressing neonatal myosin heavy chain and vimentin, did not differ significantly between patients with FSHD1A (1.1 ± 2.9%) and patients with BMD (1.8 ± 1.9%). Regeneration was not correlated with the number of KpnI restriction fragment repeats, an FSHD1A-defining genotype property within the D4Z4 locus, or overall disease severity in patients with FSHD1A. Macrophages were more prevalent in FSHD1A (0.50 ± 0.63 per mm2) vs BMD (0.07 ± 0.07 per mm2), whereas inflammatory T cells were equally infrequent. Conclusions Macrophages were more prevalent in patients with FSHD1A and could be an important pathogenic mechanism for the initiation of the dystrophic process. Furthermore, regeneration was unrelated to genotype and disease severity in FSHD1A. [ABSTRACT FROM AUTHOR]

Identification of fetal kidney anomalies invites questions about underlying causes and recurrence risk in future pregnancies. We therefore investigated the diagnostic yield of next‐generation sequencing in fetuses with bilateral kidney anomalies and the correlation between disrupted genes and fetal phenotypes. Fetuses with bilateral kidney anomalies were screened using an in‐house‐designed kidney‐gene panel. In families where candidate variants were not identified, whole‐exome sequencing was performed. Genes uncovered by this analysis were added to our kidney panel. We identified likely deleterious variants in 11 of 56 (20%) families. The kidney‐gene analysis revealed likely deleterious variants in known kidney developmental genes in 6 fetuses and TMEM67 variants in 2 unrelated fetuses. Kidney histology was similar in the latter 2 fetuses—presenting a distinct prenatal form of nephronophthisis. Exome sequencing identified ROBO1 variants in one family and a GREB1L variant in another family. GREB1L and ROBO1 were added to our kidney‐gene panel and additional variants were identified. Next‐generation sequencing substantially contributes to identifying causes of fetal kidney anomalies. Genetic causes may be supported by histological examination of the kidneys. This is the first time that SLIT‐ROBO signaling is implicated in human bilateral kidney agenesis. [ABSTRACT FROM AUTHOR]

Klinefelter syndrome ( KS, 47, XXY) is associated with increased psychiatric morbidity and cognitive disabilities, although the neuropsychological phenotype shows great variability. Androgen receptor polymorphism ( CAG repeat length), skewed X-chromosome inactivation and parent-of-origin of the extra X-chromosome have been suggested to influence cognitive function and psychological traits. These issues have not been clarified for KS patients. We studied X-chromosome inactivation pattern, CAG repeat length and parent-of-origin in relation to educational and cohabitation status, personality and autism traits, psychological distress, cognitive function and brain volumes in 73 KS patients and 73 controls. Grey matter (GM) volume of left insula was significantly decreased in KS patients with skewed X-inactivation ( z = 5.78) and we observed a borderline significant difference in global brain matter volume where KS patients with skewed X-chromosome inactivation tended to have smaller brains. Skewed X-inactivation, CAG repeat length and parent-of-origin were not correlated with educational and marital status, personality traits, autism traits, and psychological distress, prevalence of depression and anxiety or cognitive function. Interestingly our results regarding brain volumes indicate that X-inactivation has an influence on GM volume in left insula and might also be related to global GM volume, indicating a possible effect of X-linked genes on the development of GM volume in KS patient. Skewed X-inactivation, CAG repeat length and parent-of-origin have no impact on the neuropsychological phenotype in KS ( (Clinical trial NCT00999310)). [ABSTRACT FROM AUTHOR]

Dystrophic epidermolysis bullosa pruriginosa (DEB-Pr) (OMIM 604129) represents a distinct variant within the DEB clinical spectrum. It is characterized by intense pruritus and distinctive nodular prurigo-like and/or hypertrophic lichenoid lesions mainly localized on the arms, legs and upper shoulders. DEB-Pr is caused by either dominant (DDEB-Pr) or recessive mutations in the COL7A1 gene encoding type VII collagen (COLVII). The full spectrum of COL7A1 mutations in DEB-Pr remains elusive and the genotype-phenotype correlation is largely incomplete. Here, we report and functionally characterize a previously unrecognized translationally silent exonic COL7A1 mutation that results in skipping of exon 87 and is associated with DDEB-Pr phenotypes in several members of three apparently unrelated Danish families. A haplotype segregation study suggested a common ancestor in these kindred. Functional splicing analysis of the mutant exon by a COL7A1 minigene construct and computational prediction for splicing regulatory cis-sequences prove that the mutation alters the activity of an exonic splicing enhancer (ESE) critical for exon inclusion. These findings substantiate for the first time the involvement of an ESE mutation in the pathogenesis of DEB and have implications for genetic counselling of Danish families with DDEB. [ABSTRACT FROM AUTHOR]

In order to elucidate the molecular basis and the clinical characteristics of X-linked recessive nephrogenic diabetes insipidus (CNDI) in a kindred of Danish descent, we performed direct sequencing of the arginine vasopressin receptor 2 (AVPR2) gene in five members of the family, as well as clinical investigations comprising a fluid deprivation test and a 1-deamino-8-D-argininevasopressin (dDAVP) infusion test in the study subject and his mother. We found a highly unusual, novel, de novo 1447A→C point mutation (gDNA), involving the invariable splice acceptor of the second intron of the gene in both the affected male (hemizygous) and his mother (heterozygous). This mutation is likely to cause aberrant splicing of the terminal intron of the gene, leading to a non-functional AVP receptor. The clinical studies were consistent with such a hypothesis, as the affected subject had a severe insensitivity to both the antidiuretic and the coagulation factors stimulatory actions of AVP and its analogue dDAVP. Direct sequencing of the AVPR2 is an accurate and rapid diagnostic tool for CNDI and early referral of patients for AVPR2 sequencing is therefore strongly suggested. [ABSTRACT FROM AUTHOR]