Targeted gene sequencing and whole-exome sequencing in autopsied fetuses with prenatally diagnosed kidney anomalies.

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.

Antifibrotic effect after low-dose imatinib mesylate treatment in patients with nephrogenic systemic fibrosis: an open-label non-randomized, uncontrolled clinical trial.

BACKGROUND: Nephrogenic systemic fibrosis is a disease affecting the connective tissue of the skin and internal organs in patients with renal failure. No effective treatments are available. OBJECTIVES: To investigate if the tyrosine kinase inhibitor, imatinib mesylate was effective in patients with moderate to severe nephrogenic systemic fibrosis. METHODS: Among 25 patients with nephrogenic systemic fibrosis evaluated for the study from 1 October 2009 to 1 December 2010, four were included. They were treated with oral imatinib mesylate at a start dose of 400 mg/day. MAIN OUTCOME MEASURE: Reduction of skin fibrosis and increase in joint mobility evaluated by the modified Rodnan skin score and a goniometer. RESULTS: In two patients, the imatinib mesylate dose was reduced to 200 mg/day and in one patient to 100 mg/day. Two patients were treated for 24 weeks, one patient for 16 weeks and one patient for 4 weeks. Three patients experienced tethering of their skin which lessened with reduction in modified Rodnan skin score from 24 to 20, 24 to 17 and 21 to 14 but with very limited changes in joint mobility. The fourth patient discontinued the treatment due to a complicating infection. CONCLUSION: Imatinib mesylate may be an effective drug in the treatment of skin fibrosis in moderate to severe NSF cases, even at reduced doses. We found a positive clinical effect on the skin, but no convincing improvement of the joint mobility. Only few patients could be recruited limiting the interpretation and conclusions of the results.

Nephrogenic systemic fibrosis is found only among gadolinium-exposed patients with renal insufficiency: a case-control study from Denmark.

BACKGROUND: Nephrogenic systemic fibrosis (NSF) is a systemic fibrosing disease associated with exposure to gadolinium-based contrast agents (GBCA) in patients with renal insufficiency. OBJECTIVES: To report the prevalence of NSF in a well-defined cohort of patients with renal insufficiency exposed to GBCA, to investigate if GBCA-unexposed controls showed signs of NSF and to evaluate selected risk factors among NSF cases and GBCA-exposed controls. METHODS: A study among GBCA-exposed patients with renal insufficiency (n=565) was conducted to identify cases of NSF. The NSF cases found were age and sex matched and clinically compared with GBCA-exposed and unexposed patients with renal insufficiency in a case-control study. RESULTS: We identified 17 NSF cases. No signs of NSF were observed among the controls. The prevalence of NSF was 4·7%, highest among patients with chronic kidney disease (CKD) stage 5 exposed to GBCA and undergoing haemodialysis or peritoneal dialysis. Three NSF cases were identified among patients with CKD stage 3 and 4. Three patients developed NSF after macrocyclic GBCA exposure. NSF cases had a tendency to have higher serum phosphate concentrations than GBCA-exposed controls. CONCLUSIONS: Our study supports the view that GBCA is a major risk factor for NSF. Importantly, we found that patients with CKD stage 3 and 4 can be at risk of NSF. NSF may also be triggered by macrocyclic GBCA. Further, we observed a trend for higher phosphate levels in NSF cases compared with controls. The important findings drawn from this case-control study indicate that NSF is not an overlooked condition among patients with renal insufficiency not exposed to GBCA.

A novel mutation in the connexin 26 gene (GJB2) in a child with clinical and histological features of keratitis-ichthyosis-deafness (KID) syndrome.

BACKGROUND: Keratitis-ichthyosis-deafness (KID) syndrome is a rare congenital ectodermal disorder, caused by heterozygous missense mutation in GJB2, encoding the gap junction protein connexin 26. The commonest mutation is the p.Asp50Asn mutation, and only a few other mutations have been described to date. AIM: To report the fatal clinical course and characterize the genetic background of a premature male neonate with the clinical and histological features of KID syndrome. METHODS: Genomic DNA was extracted from peripheral blood and used for PCR amplification of the GJB2 gene. Direct sequencing was used for mutation analysis. RESULTS: The clinical features included hearing impairment, ichthyosiform erythroderma with hyperkeratotic plaques, palmoplantar keratoderma, alopecia of the scalp and eyelashes, and a thick vernix caseosa-like covering of the scalp. On histological analysis, features characteristic of KID syndrome, such as acanthosis and papillomatosis of the epidermis with basket-weave hyperkeratosis, were seen. The skin symptoms were treated successfully with acitretin 0.5 mg/kg. The boy developed intraventricular and intracerebral haemorrhage, leading to hydrocephalus. His condition was further complicated by septicaemia and meningitis caused by infection with extended-spectrum beta-lactamase-producing Klebsiella pneumoniae. Severe respiratory failure followed, and the child died at 46 weeks of gestational age (13 weeks postnatally). Sequencing of the GJB2 gene showed that the child was heterozygous for a novel nucleotide change, c.263C>T, in exon 2, leading to a substitution of alanine for valine at position 88 (p.Ala88Val). CONCLUSIONS: This study has identified a new heterozygous de novo mutation in the Cx26 gene (c.263C>T; p.Ala88Val) leading to KID syndrome.

Low incidence of UPD in spontaneous abortions beyond the 5th gestational week.

Approximately 15-20% of all clinically recognised pregnancies abort, most commonly between 8-12 gestational weeks. While the majority of early pregnancy losses is attributed to cytogenetic abnormalities, the aetiology of approximately 40% of early abortions remains unclear. To determine additional factors causing spontaneous abortions we retrospectively searched for uniparental disomies (UPD) in 77 cytogenetically normal diploid spontaneous abortions. In all cases an unbalanced chromosome anomaly was ruled out by cytogenetic investigation of chorionic/amniotic membranes and/or chorionic villi. For UPD screening microsatellite analyses were performed on DNA of abortion specimens and parental blood using highly polymorphic markers showing UPD in two cases. The distribution of markers analysed indicated maternal heterodisomy for chromosome 9 (UPhD(9)mat) in case 1 and paternal isodisomy for chromosome 21 (UPiD(21)pat) in case 2. The originating mechanism suggested was monosomy complementation in UPiD(21)pat and trisomy rescue in UPhD(9)mat. In the case of UPhD(9)mat purulent chorioamnionitis was noted and a distinctly growth retarded embryo of 3 cm crown-rump length showing no gross external malformations. Histological analysis in the case of UPiD(21)pat suggested a primary anlage defect. Our results indicate that less than 3% of genetically unexplained pregnancy wastage is associated with total chromosome UPD. UPD may contribute to anlage defects of human conception. Chromosome aneuploidy correction can occur in very early cleavage stages. More research, however, ought to be performed into placental mosaicism to further clarify timing and mechanisms involved in foetal UPD.

Variability in the phenotypic expression of fryns syndrome: A report of two sibships.

We report on two sibships with four fetuses of 12, 15, 17, and 20 weeks of gestation, respectively, and 1 preterm baby of 31 weeks of gestation affected by a multiple congenital disorder with manifestation suggestive of Fryns syndrome. In addition to the characteristic malformation pattern in Fryns syndrome, they presented with fetal hydrops, cystic hygroma, and multiple pterygias, allowing prenatal ultrasound diagnosis as early as in the 11th week of gestation. The two affected fetuses of family 1 showed severe craniofacial anomalies with bilateral cleft lip and palate, acral hypoplasia, postaxial oligodactyly, persistent truncus arteriosus, and interrupted aortic arch, asplenia sequence, and complex central nervous system midline malformations. In family 2 with three affected sibs, ear anomalies with atresia of the auditory canals, postaxial hexadactyly, intestinal atresias, callosal defects, and eye colobomas were the most outstanding features. On the basis of the present findings and former reports, the inter- and intrafamiliar phenotypic variability in Fryns syndrome, possible pathogenetic mechanisms, and the value of prenatal diagnosis are discussed. In the pathogenetic discussion, a special emphasis is put on the neural crest cell developmental field.

[Pathologic embryo examinations of induced and spontaneous abortions in the 1st trimester of pregnancy]. / Embryopathologische Untersuchungen an induzierten und spontanen Aborten im 1. Schwangerschaftstrimenon.

Morphological examination methods which are appropriate for detection of embryonic developmental defects are presented. The main emphasis is put on autopsy of small embryos using a dissection microscope and on documentation of the embryonic skeleton by means of skeleton staining. Through presentation of the embryopathological findings in 15 first-trimester abortion specimens we demonstrate that these examination techniques frequently allow diagnosis of isolated malformations as well as malformation syndromes, even in the fragmented or macerated embryo. Careful embryopathological examination and evaluation is a precondition for genetic counselling, as well as for goal-directed prenatal diagnostic measures in future pregnancies.

Normal karyotype in cultured chorionic villus cells, but mosaicism in amniotic and fetal cells.

A case with a normal male karyotype in cultured chorionic villus cells, but 46,XY/45,X/46,X,i(Yq) mosaicism in amniotic and fetal tissue is reported. The fetus was a phenotypic male. Pathological examination revealed discrete features, which might indicate a syndrome, and histological examination showed large, bright cells in the tubules of the testes. Possible explanations for discordance between the karyotype of embryonic and extraembryonic tissue are discussed.

[Fetal pathology--in relation to prenatal diagnosis and genetic counseling]. / Føtalpatologi--i relation til praenatal diagnostik og genetisk rådgivning.

The results of systematic autopsies of 29 fetuses from a consecutive material consisting of 19 late spontaneous abortions and four induced abortions from the Department of Gynaecology and Obstetrics in the Municipal Hospital in Arhus are presented. Where the spontaneous abortions were concerned, a cause of the abortion was revealed in 15 out of 19 cases (79%). Infection caused eight abortions, pathological placental conditions caused four, umbilical cord complications one case, an IUD in utero one case and severe fetal malformations one case. Serious congenital malformations were present in six out of the total number of 29 fetuses (21%). The diagnoses could be established in five cases and the risk of recurrence could be assessed. Increased fetal pathological activity in the form of systemic fetal pathological examinations will result in improved genetic counselling, more certain prenatal diagnosis and improved understanding of the pathogenesis of congenital deformities.

Fraser syndrome (cryptophthalmos with syndactyly) in the fetus and newborn.

Clinical and autopsy findings in two fetuses and one newborn infant with Fraser syndrome are presented. Discussion focuses on the range of phenotypic expression within this autosomal-recessive disorder, the resulting difficulties in prenatal and postnatal diagnosis, and on the concept of a neurocristopathy as underlying disturbance.