Shariant platform: Enabling evidence sharing across Australian clinical genetic-testing laboratories to support variant interpretation

Sharing genomic variant interpretations across laboratories promotes consistency in variant assertions. A landscape analysis of Australian clinical genetic-testing laboratories in 2017 identified that, despite the national-accreditation-body recommendations encouraging laboratories to submit genotypic data to clinical databases, fewer than 300 variants had been shared to the ClinVar public database. Consultations with Australian laboratories identified resource constraints limiting routine application of manual processes, consent issues, and differences in interpretation systems as barriers to sharing. This information was used to define key needs and solutions required to enable national sharing of variant interpretations. The Shariant platform, using both the GRCh37 and GRCh38 genome builds, was developed to enable ongoing sharing of variant interpretations and associated evidence between Australian clinical genetic-testing laboratories. Where possible, two-way automated sharing was implemented so that disruption to laboratory workflows would be minimized. Terms of use were developed through consultation and currently restrict access to Australian clinical genetic-testing laboratories. Shariant was designed to store and compare structured evidence, to promote and record resolution of inter-laboratory classification discrepancies, and to streamline the submission of variant assertions to ClinVar. As of December 2021, more than 14,000 largely prospectively curated variant records from 11 participating laboratories have been shared. Discrepant classifications have been identified for 11% (28/260) of variants submitted by more than one laboratory. We have demonstrated that co-design with clinical laboratories is vital to developing and implementing a national variant-interpretation sharing effort. This approach has improved inter-laboratory concordance and enabled opportunities to standardize interpretation practices.

CD36 polymorphisms and the age of disease onset in patients with pathogenic variants within the mutation cluster region of APC

Background

Familial adenomatous polyposis (FAP) is an autosomal dominant condition that predisposes patients to colorectal cancer. FAP is the result of a loss of APC function due to germline pathogenic variants disrupting gene expression. Genotype-phenotype correlations are described for FAP. For example attenuated forms of the disease are associated with pathogenic variants at the 5’ and 3’ ends of APC whilst severe forms of the disease appear to be linked to variants occurring in the mutation cluster region (MCR) of the gene. Variants occurring in the MCR are phenotypically associated with hundreds to thousands of adenomas carpeting the colon and rectum and patients harbouring changes in this region have a high propensity to develop colorectal cancer. Not all patients who carry pathogenic variants in this region have severe disease which may be a result of environmental factors. Alternatively, phenotypic variation observed in these patients could be due to modifier genes that either promote or inhibit disease expression. Mouse models of FAP have provided several plausible candidate modifier genes, but very few of these have survived scrutiny. One such genetic modifier that appears to be associated with disease expression is CD36. We previously reported a weak association between a polymorphism in CD36 and a later age of disease onset on a relatively small FAP patient cohort.

Methods

In the current study, we enlarged the FAP cohort. 395 patients all carrying pathogenic variants in APC were tested against three CD36 Single Nucleotide Polymorphisms (SNP)s (rs1049673, rs1761667 rs1984112), to determine if any of them were associated with differences in the age of disease expression.

Results

Overall, there appeared to be a statistically significant difference in the age of disease onset between carriers of the variant rs1984112 and wildtype. Furthermore, test equality of survivor functions for each SNP and mutation group suggested an interaction in the Log Rank, Wilcoxon, and Tarone-Ware methods for rs1049673, rs1761667, and rs1984112, thereby supporting the notion that CD36 modifies disease expression.

Conclusions

This study supports and strengthens our previous findings concerning CD36 and an association with disease onset in FAP, AFAP and FAP-MCR affected individuals. Knowledge about the role CD36 in adenoma development may provide greater insight into the development of colorectal cancer.

Targeted sequencing of genes associated with the mismatch repair pathway in patients with endometrial cancer

Germline variants inactivating the mismatch repair (MMR) genes MLH1, MSH2, MSH6 and PMS2 cause Lynch syndrome that implies an increased cancer risk, where colon and endometrial cancer are the most frequent. Identification of these pathogenic variants is important to identify endometrial cancer patients with inherited increased risk of new cancers, in order to offer them lifesaving surveillance. However, several other genes are also part of the MMR pathway. It is therefore relevant to search for variants in additional genes that may be associated with cancer risk by including all known genes involved in the MMR pathway. Next-generation sequencing was used to screen 22 genes involved in the MMR pathway in constitutional DNA extracted from full blood from 199 unselected endometrial cancer patients. Bioinformatic pipelines were developed for identification and functional annotation of variants, using several different software tools and custom programs. This facilitated identification of 22 exonic, 4 UTR and 9 intronic variants that could be classified according to pathogenicity. This study has identified several germline variants in genes of the MMR pathway that potentially may be associated with an increased risk for cancer, in particular endometrial cancer, and therefore are relevant for further investigation. We have also developed bioinformatics strategies to analyse targeted sequencing data, including low quality data and genomic regions outside of the protein coding exons of the relevant genes.

Novel de novo TRIP12 mutation reveals variable phenotypic presentation while emphasizing core features of TRIP12 variations

Intellectual disability (ID) is a complicated and multifactorial condition often with an unclear cause. Advancements in diagnostic techniques have identified genetic causes in a significant proportion. Pathogenic variants in TRIP12, encoding for an E3 ligand in the ubiquitin-protease pathway, have previously been identified as a cause of ID with autistic behavior and dysmorphic features. We report two unrelated patients with de novo mutations in TRIP12 and diagnoses of global developmental delay, autism spectrum disorder and dysmorphic features, as well as a range of other characteristics. Exome sequencing was utilized as part of an extensive genetic workup for both individuals. The genotypic and phenotypic data for both patients has been collated with previously reported data. Epilepsy was noted in about 20% published cases. One of our patents had epilepsy. These cases highlight the variable phenotypic presentations of TRIP12 variations while emphasizing the core features of ID and speech delay, with or without autistic features and epilepsy.

Is a fractured mandible an emergency?

We retrospectively audited the records of 708 patients who presented with the diagnosis of fractured mandible between January 2009 and July 2013 at the Queen Elizabeth Hospital, Birmingham. We assessed the different factors that may have altered their outcomes, and found that delay before definitive fixation caused no harm in either the short or the long term.

When is a mutation not a mutation: the case of the c.594-2A>C splice variant in a woman harbouring another BRCA1 mutation in trans

Since the identification of BRCA1 there has only ever been described two bi-allelic mutation carriers, one of whom was subsequently shown to be a mono-allelic carrier. The second patient diagnosed with two BRCA1 mutations appears to be accurate but there remain some questions about the missense variant identified in that patient. In this report we have identified a woman who is a bi-allelic mutation carrier of BRCA1 and provide an explanation as to why this patient has a phenotype very similar to that of any mono-allelic mutation carrier. The splice variant identified in this patient appears to be associated with the up-regulation of a BRCA1 splice variant that rescues the lethality of being a double mutant. The consequences of the findings of this report may have implications for mutation interpretation and that could serve as a model for not only BRCA1 but also for other autosomal dominant disorders that are considered as being embryonically lethal.

Targeted next-generation sequencing of 22 mismatch repair genes identifies Lynch syndrome families

Causative germline mutations in mismatch repair (MMR) genes can only be identified in ~50% of families with a clinical diagnosis of the inherited colorectal cancer (CRC) syndrome hereditary nonpolyposis colorectal cancer (HNPCC)/Lynch syndrome (LS). Identification of these patients are critical as they are at substantially increased risk of developing multiple primary tumors, mainly colorectal and endometrial cancer (EC), occurring at a young age. This demonstrates the need to develop new and/or more thorough mutation detection approaches. Next‐generation sequencing (NGS) was used to screen 22 genes involved in the DNA MMR pathway in constitutional DNA from 14 HNPCC and 12 sporadic EC patients, plus 2 positive controls. Several softwares were used for analysis and functional annotation. We identified 5 exonic indel variants, 42 exonic nonsynonymous single‐nucleotide variants (SNVs) and 1 intronic variant of significance. Three of these variants were class 5 (pathogenic) or class 4 (likely pathogenic), 5 were class 3 (uncertain clinical relevance) and 40 were classified as variants of unknown clinical significance. In conclusion, we have identified two LS families from the sporadic EC patients, one without a family history of cancer, supporting the notion for universal MMR screening of EC patients. In addition, we have detected three novel class 3 variants in EC cases. We have, in addition discovered a polygenic interaction which is the most likely cause of cancer development in a HNPCC patient that could explain previous inconsistent results reported on an intronic EXO1 variant.

Lynch syndrome mutation spectrum in New South Wales, Australia, including 55 novel mutations

Background

Lynch syndrome, the most frequent hereditary colorectal cancer syndrome, is caused by defects in mismatch repair genes. Genetic testing is important in order to identify mutation carriers who can benefit from intensive surveillance programs. One of the challenges with genetic testing is the interpretation of pathogenicity of detected DNA variants. The aim of this study was to investigate all putative pathogenic variants tested for at the Division of Molecular Medicine, Pathology North, in Newcastle, Australia, to establish whether previous variant classification is in accordance with that recently performed in the InSiGHT collaboration.

Methods

Prediction programs and available literature were used to classify new variants or variants without classification.

Results

We identified 333 mutation positive families, in which 211 different putative pathogenic mismatch repair mutations were found. Most variants with an InSiGHT classification (141 out of 146) were in accordance with our classification. Five variants were discordant, of which one can definitively be reclassified according to the InSiGHT scheme as class 5. Sixty‐four variants had not been classified by InSiGHT, of whom 55 have not been previously reported.

Conclusion

In conclusion, we found that our classifications were mostly in accordance with the InSiGHT scheme. In addition to already known MMR mutations, we have also presented 55 novel pathogenic or putative pathogenic mutations.

Combined analysis of three Lynch syndrome cohorts confirms the modifying effects of 8q23.3 and 11q23.1 in MLH1 mutation carriers

Two colorectal cancer (CRC) susceptibility loci have been found to be significantly associated with an increased risk of CRC in Dutch Lynch syndrome (LS) patients. Recently, in a combined study of Australian and Polish LS patients, only MLH1 mutation carriers were found to be at increased risk of disease. A combined analysis of the three data-sets was performed to better define this association. This cohort-study includes three sample populations combined totaling 1,352 individuals from 424 families with a molecular diagnosis of LS. Seven SNPs, from six different CRC susceptibility loci, were genotyped by both research groups and the data analyzed collectively. We identified associations at two of the six CRC susceptibility loci in MLH1 mutation carriers from the combined LS cohort: 11q23.1 (rs3802842, HR = 2.68, p ≤ 0.0001) increasing risk of CRC, and rs3802842 in a pair-wise combination with 8q23.3 (rs16892766) affecting age of diagnosis of CRC (log-rank test; p ≤ 0.0001). A significant difference in the age of diagnosis of CRC of 28 years was observed in individuals carrying three risk alleles compared to those with 0 risk alleles for the pair-wise SNP combination. A trend (due to significance threshold of p ≤ 0.0010) was observed in MLH1 mutation carriers towards an increased risk of CRC for the pair-wise combination (p = 0.002). This study confirms the role of modifier loci in LS. We consider that LS patients with MLH1 mutations would greatly benefit from additional genotyping of SNPs rs3802842 and rs16892766 for personalized risk assessment and a tailored surveillance program.

Colorectal cancer susceptibility loci on chromosome 8q23.3 and 11q23.1 as modifiers for disease expression in Lynch syndrome

OBJECTIVE

Recently, six colorectal cancer (CRC) susceptibility loci have been identified, and two single-nucleotide polymorphisms (SNPs)--rs16892766 (8q23.3) and rs3802842 (11q23.1)--from two of these regions have been found to be significantly associated with an increased CRC risk in patients with Lynch syndrome. The objective of this study was to genotype nine SNPs within these six loci to confirm previous findings and investigate whether they act as modifiers of disease risk in patients with Lynch syndrome.

DESIGN

The patient cohort consisted of 684 mutation-positive patients with Lynch syndrome from 298 Australian and Polish families. Nine SNPs were genotyped: rs16892766 (8q23.3), rs7014346 and rs6983267 (8q24.21), rs10795668 (10p14), rs3802842 (11q23.1), rs10318 and rs4779584 (15q13.3), and rs4939827 and rs4464148 (18q21.1). The data were analysed to investigate possible associations between the presence of variant alleles and the risk of developing disease.

RESULTS

An association between SNP rs3802842 on chromosome 11q23.1 and rs16892766 on chromosome 8q23.3 and the risk of developing CRC and age of diagnosis was found in MLH1 mutation carriers. Female MLH1 mutation carriers harbouring the homozygous variant genotype for SNP rs3802842 have the highest risk of developing CRC. When the number of risk alleles for the two SNPs combined was analysed, a difference of 24 years was detected between individuals carrying three risk alleles and those carrying no risk alleles.

CONCLUSION

The authors were able to replicate the association between the CRC susceptibility loci on chromosomes 8q23.3 and 11q23 and the risk of developing CRC in patients with Lynch syndrome, but the association could only be detected in MLH1 mutation carriers in this study.

MSH6 and PMS2 mutation positive Australian Lynch syndrome families: novel mutations, cancer risk and age of diagnosis of colorectal cancer

BACKGROUND

Approximately 10% of Lynch syndrome families have a mutation in MSH6 and fewer families have a mutation in PMS2. It is assumed that the cancer incidence is the same in families with mutations in MSH6 as in families with mutations in MLH1/MSH2 but that the disease tends to occur later in life, little is known about families with PMS2 mutations. This study reports on our findings on mutation type, cancer risk and age of diagnosis in MSH6 and PMS2 families.

METHODS

A total of 78 participants (from 29 families) with a mutation in MSH6 and 7 participants (from 6 families) with a mutation in PMS2 were included in the current study. A database of de-identified patient information was analysed to extract all relevant information such as mutation type, cancer incidence, age of diagnosis and cancer type in this Lynch syndrome cohort. Cumulative lifetime risk was calculated utilising Kaplan-Meier survival analysis.

RESULTS

MSH6 and PMS2 mutations represent 10.3% and 1.9%, respectively, of the pathogenic mutations in our Australian Lynch syndrome families. We identified 26 different MSH6 and 4 different PMS2 mutations in the 35 families studied. We report 15 novel MSH6 and 1 novel PMS2 mutations. The estimated cumulative risk of CRC at age 70 years was 61% (similar in males and females) and 65% for endometrial cancer in MSH6 mutation carriers. The risk of developing CRC is different between males and females at age 50 years, which is 34% for males and 21% for females.

CONCLUSION

Novel MSH6 and PMS2 mutations are being reported and submitted to the current databases for identified Lynch syndrome mutations. Our data provides additional information to add to the genotype-phenotype spectrum for both MSH6 and PMS2 mutations.

Deletion Mutations in an Australian Series of HNPCC Patients

Hereditary non polyposis colorectal cancer (HNPCC) is characterized by the presence of early onset colorectal cancer and other epithelial malignancies. The genetic basis of HNPCC is a deficiency in DNA mismatch repair, which manifests itself as DNA microsatellite instability in tumours. There are four genes involved in DNA mismatch repair that have been linked to HNPCC; these include hMSH2, hMLH1, hMSH6 and hPMS2. Of these four genes hMLH1 and hMSH2 account for the majority of families diagnosed with the disease. Notwithstanding, up to 40 percent of families do not appear to harbour a change in either hMSH2 or hMLH1 that can be detected using standard screening procedures such as direct DNA sequencing or a variety of methods all based on a heteroduplex analysis.In this report we have screened a series of 118 probands that all have the clinical diagnosis of HNPCC for medium to large deletions by the Multiplex Ligation-Dependent Probe Amplification assay (MLPA) to determine the frequency of this type of mutation. The results indicate that a significant proportion of Australian HNPCC patients harbour deletion or duplication mutations primarily in hMSH2 but also in hMLH1.

Hereditary non-polyposis colorectal cancer and the role of hPMS2 and hEXO1 mutations

Hereditary non-polyposis colorectal cancer (HNPCC) is an autosomal dominant, inherited condition that is characterized primarily by the development of early-onset colorectal cancer and a number of other epithelial malignancies. The underlying genetic basis of the disease is associated with a breakdown of DNA-mismatch repair. There are many genes involved in DNA-mismatch repair, and five of them have been implicated in HNPCC. Two of the genes (hMSH2 and hMLH1) account for the majority of HNPCC families (approximately 60%), and it is not known what the exact contributions of the remaining three genes (hPMS1, hPMS2, and hMSH6) are in relation to this condition. In addition, a sixth gene (hEXO1) has been associated with a disease phenotype that is consistent with HNPCC. Current estimates suggest that all four of these genes, combined, may account for up to 5% of families. In this report, we examine the contribution of hPMS2 and hEXO1 to a well-defined set of families that fulfill the diagnostic criteria for HNPCC. The genes, hPMS2 and hEXO1, were studied by denaturing high performance liquid chromatography (DHPLC) analysis in 21 families that have previously been determined not to have mutations in hMSH2 or hMLH1. hPMS2 accounts for a small proportion of HNPCC families, and none were deemed to be associated with hEXO1. Mutations in hPMS2 appear to account for a small proportion of families adhering to the Amsterdam II criteria, whereas hEXO1 does not appear to be associated with HNPCC.

Prevalence of persistent primary reflexes and motor problems in children with reading difficulties

It has been shown that some children with reading difficulties have underlying developmental delay and that this may be related to the persistence of primary reflexes. This study investigated the prevalence of persistent primary reflexes in the ordinary primary school population and how this related to other cognitive and social factors. Three groups of 41 children were drawn from a representative, cross-sectional sample of 409 children (aged 9-10 years) attending 11 ordinary primary schools in N. Ireland. The three groups represented the bottom, middle and top 10% respectively of readers from the total sample population. The relative persistence (on a scale of 0 to 4) of the Asymmetrical Tonic Neck Reflex (ATNR) and the prevalence of motor difficulties were assessed for these 3 groups. The rôle of 5 predictor variables (verbal IQ, social deprivation, sex, month of birth and religious affiliation) in determining the reading level of the total sample was also investigated. It was found that the lowest reading group had a significantly higher mean level of ATNR (1.56 [95% CI 1.22-1.90]) compared with the middle reading group (0.56 [0.22-0.90]) and the top reading group (0.59 [0.25-0.92]). 17% of children in the lowest reading group had extremely high levels of the ATNR while 24% showed no presence of ATNR. This contrasted with 0% and 66%, respectively for both middle and top reading groups. It was also found that there was a significant difference between the lowest reading group and the top reading group on a standardised test of motor ability. Furthermore, there was evidence that ATNR persistence but not motor ability was associated with the sex of the child with boys, in particular, at risk. There was no evidence that ATNR persistence or motor ability was significantly associated with social deprivation. It was also found that there were no significant differences between dyslexic and non-dyslexic children with reading difficulties in motor (including balance) performance. This study highlights the high levels of primary reflex persistence in children with reading difficulties and it provides further evidence of the association between reading difficulties and movement difficulties in young children. However, while the implications for intervention are discussed, it is stressed that the persistence of primary reflexes cannot be used as a causal model for reading difficulties, including dyslexia.

Cerebral atrophy following shaken impact syndrome and other non-accidental head injury (NAHI)

PURPOSE OF THE STUDY

To determine the frequency of cerebral atrophy and microcephaly in a group of children with sequential MRI brain scans after surviving a non-accidental head injury (n = 16).

METHODS

Serial head circumference measurements (OFC) were extracted and plotted on standard growth charts for each child retrospectively to determine the frequency of secondary microcephaly. Cerebral atrophy was diagnosed and quantified by measurement of the ventricular/cortical ratio on coronal images of the sequential scans.

RESULTS

Acquired microcephaly was found in 15 children (93.8%) over a median follow-up period of 67.93 weeks. There was a significant reduction in the median Z-score for the OFC at the most recent follow-up when compared with that at presentation (p < 0.001, Wilcoxon Signed Rank Test). Cerebral atrophy was found to be the cause of the microcephaly in eight of the 15 children and was evident as early as 9 days after presentation.

CONCLUSION

A large proportion of the cohort (93.8%) develops acquired microcephaly after an inflicted head injury and cerebral atrophy is responsible in half of these cases.

A Comparison Between Denaturing Gradient Gel Electrophoresis and Denaturing High Performance Liquid Chromatography in Detecting Mutations in Genes Associated with Hereditary Non-Polyposis Colorectal Cancer (HNPCC) and the Identification of 9 New Mutations Previously Unidentified by DGGE

Denaturing high performance liquid chromatography is a relatively new method by which heteroduplex structures formed during the PCR amplification of heterozygote samples can be rapidly identified. The use of this technology for mutation detection in hereditary non-polyposis colorectal cancer (HNPCC) has the potential to appreciably shorten the time it takes to analyze genes associated with this disorder. Prior to acceptance of this method for screening genes associated with HNPCC, assessment of the reliability of this method should be performed. In this report we have compared mutation and polymorphism detection by denaturing gradient gel electrophoresis (DGGE) with denaturing high performance liquid chromatography (DHPLC) in a set of 130 families. All mutations/polymorphisms representing base substitutions, deletions, insertions and a 23 base pair inversion were detected by DHPLC whereas DGGE failed to identify four single base substitutions and a single base pair deletion. In addition, we show that DHPLC has been used for the identification of 5 different mutations in exon 7 of hMSH2 that could not be detected by DGGE.

From this study we conclude that DHPLC is a more effective and rapid alternative to the detection of mutations in hMSH2 and hMLH1 with the same or better accuracy than DGGE. Furthermore, this technique offers opportunities for automation, which have not been realised for the majority of other methods of gene analysis.

Mutation analysis of the STK11/LKB1 gene and clinical characteristics of an Australian series of Peutz-Jeghers syndrome patients

Peutz-Jeghers syndrome (PJS) is a rare cancer predisposition, which is characterized by the presence of hamartomatous polyposis and mucocutaneous pigmentation. A significant proportion of both familial and sporadic forms of this disorder are associated with mutations in the STK11 (serine/threonine kinase 11)/LKB1 gene. In this report we present a series of Australian PJS cases, which suggest that mutations in the STK11 gene do not account for many families or patients without a family history. The most likely explanation is either the presence of another susceptibility gene or genetic mosaicism in the non-familial patients.

Hereditary nonpolyposis colorectal cancer in 95 families: differences and similarities between mutation-positive and mutation-negative kindreds

Hereditary nonpolyposis colorectal cancer (HNPCC) describes the condition of a disparate group of families that have in common a predisposition to colorectal cancer in the absence of a premalignant phenotype. The genetic basis of this disease has been linked to mutations in genes associated with DNA mismatch repair. A large proportion of families harbor changes in one of two genes, hMSH2 and hMLH1. Approximately 35% of families in which the diagnosis is based on the Amsterdam criteria do not appear to harbor mutations in DNA-mismatch-repair genes. In this report we present data from a large series of families with HNPCC and indicate that there are subtle differences between families that harbor germline changes in hMSH2 and families that harbor hMLH1 mutations. Furthermore, there are differences between the mutation-positive group (hMSH2 and hMLH1 combined) of families and the mutation-negative group of families. The major findings identified in this study focus primarily on the extracolonic disease profile observed between the mutation-positive families and the mutation-negative families. Breast cancer was not significantly overrepresented in the hMSH2 mutation-positive group but was overrepresented in the hMLH1 mutation-positive group and in the mutation-negative group. Prostate cancer was not overrepresented in the mutation-positive groups but was overrepresented in the mutation-negative group. In age at diagnosis of colorectal cancer, there was no difference between the hMSH2 mutation-positive group and the hMLH1 mutation-positive group, but there was a significant difference between these two groups and the mutation-negative group.

Effects of replicating primary-reflex movements on specific reading difficulties in children: a randomised, double-blind, controlled trial

BACKGROUND

Children with specific reading difficulties have problems that extend beyond the range of underlying language-related deficits (eg, they have difficulties with balance and motor control). We investigated the role of persistent primary reflexes (which are closely linked in the earliest months of life to the balance system) in disrupting the development of reading skills.

METHODS

We assessed the efficacy of an intervention programme based on replicating the movements generated by the primary-reflex system during fetal and neonatal life. A randomised, individually matched, double-blind, placebo-controlled design was used and children (aged 8-11 years) with persistent primary reflexes and a poor standard of reading were enrolled into one of three treatment groups: experimental (children were given a specific movement sequence); placebo-control (children were given non-specific movements); and control (no movements).

FINDINGS

From an initial sample of 98 children, 60 children, 20 in each group were matched on age, sex, verbal intelligence quotient (IQ), reading ability, and persistent asymmetrical tonic neck reflex. For asymmetrical tonic neck-reflex levels there was a significant (group by time) interaction (p<0.001). The experimental group showed a significant decrease in the level of persistent reflex over the course of the study (mean change -1.8 [95% CI -2.4 to -1.2], p<0.001), whereas the changes in the placebo-control and control groups were not significant (-0.2 [-0.9 to 0.6] and -0.4 [-0.9 to 0.2]).

INTERPRETATION

This study provides further evidence of a link between reading difficulties and control of movement in children. In particular, our study highlights how the educational functioning of children may be linked to interference from an early neurodevelopmental system (the primary-reflex system). A new approach to the treatment of children with reading difficulties is proposed involving assessment of underlying neurological functioning, and appropriate remediation.

Magnetic resonance imaging in acute non-accidental head injury

Making the diagnosis of non-accidental head injury, particularly in the acute illness, can be difficult. The aim of this retrospective study was to evaluate the use of magnetic resonance imaging in the acute presentation of non-accidental head injury. Twelve cases admitted to the Royal Hospital for Sick Children, Edinburgh with a diagnosis of non-accidental head injury, and who had magnetic resonance imaging in the acute illness, were identified. The average age was 5.7 mo (range 1 to 34 mo). The mechanism of the primary injury was whiplash-shaking injury syndrome with impact in four cases and without evidence of impact in seven; in one case there was a compression injury. The magnetic resonance imaging findings reflected the pathological consequences of rotational acceleration-deceleration injury and did not differ between those cases with evidence of impact and those without. Subdural haematomas were identified in all cases; the commonest location for subdural blood was the subtemporal region. It is surprising and important that the most frequent location of subdural blood was in the subtemporal area. This is an area difficult to assess by computerized tomography. Evidence of repeated injuries was found in two cases. These findings confirm the value of magnetic resonance imaging in the acute phase of non-accidental head injury.

Retinyl ethers as cancer chemopreventive agents. Suppression of mammary cancer

It had been demonstrated previously that retinyl methyl ether (RME) can suppress carcinogen-induced mammary cancers in vivo. It had also been shown that RME is demethylated enzymatically to retinol and produces the toxic effects of retinol; however, a rationale was developed for further investigations of retinyl ethers and was the basis for the synthesis and biological evaluations of new retinyl ethers for the chemoprevention of mammary cancer, reported herein. Two of the new retinyl ethers, retinyl 3-methyl-2-butenyl ether (RMBE) and retinyl 2-propynyl ether (RPE), were evaluated for the suppression of mammary cancers in vivo. RMBE, RPE, RME, the 2,3,6-trimethyl-4-methoxyphenyl analogue of RME, and retinyl acetate (a positive control) were incorporated individually into the feed of rats that had been injected with N-methyl-N-nitrosourea to induce mammary cancers. Ninety-day tests of these compounds for suppression of mammary cancer showed that RPE has significant cancer chemopreventive activity, comparable to that of retinyl acetate in simultaneous tests. RMBE demonstrated borderline activity. Both RPE and RMBE were less toxic than retinyl acetate or RME and, in contrast to the other retinoids, did not cause accumulation of large amounts of retinyl palmitate in the liver. Further investigations of RPE showed that it accumulated in mammary tissue after a single oral dose was administered to female rats, reached maximum concentrations within 24 h, and was still present at 75-80% of maximum concentrations after 72 h. In ethanol at 25 degrees C, RPE slowly underwent intramolecular cyclization; small amounts of the cyclized product also appeared in mammary tissue of rats dosed with RPE. During the mammary cancer bioassay, however, RPE was essentially stable in the feed. Some of the new retinyl ethers, as well as RME, bind to cellular retinol-binding protein.

Use of the prone position in the MRI evaluation of spinal cord retethering

In order to determine the impact of magnetic resonance imaging (MRI) in the management of spinal cord retethering, we retrospectively reviewed case and imaging records of 51 patients who underwent MRI examination in supine and prone positions. Group 1 included 8 control patients without cord tethering. They exhibited a normal level of the conus medullaris with normal surrounding subarachnoid space, and consistent anterior migration of the conus within the dural sac on MRI in prone position. Group 2 included 17 patients with tethered cord secondary to occult spinal dysraphism (spinal cord lipoma in 6 patients, thick filum terminale in 4, diastematomyelia in 4, myelomeningocele manqué in 2, and dermoid tumour in 1). Supine and prone MRI performed at a median period of time of 6 months after untethering showed resolution of posterior tethering in 5 out of the 7 patients who exhibited pre-operatively dorsal attachment of the spinal cord to the dura. Anterior migration of the conus or of the cord/filum complex in prone position was observed in only 24% of the cases. Group 3 included 26 patients with secondary tethered cord following prior myelomeningocele closure. Their MRI performed at a median interval of time of 11 months following untethering demonstrated resolution of the posterior cord tethering in only 8 out of the 24 patients who exhibited this feature pre-operatively. Anterior migration within the expanded dural sac was never noted in this group. We conclude that spine MRI is of limited value and that prone-positioned MRI is of no additional use in the evaluation of spinal cord retethering.

Ultrasound, computed tomography and magnetic resonance in the investigation of iliopsoas compartment disease

The authors reviewed the results of imaging studies performed in 30 patients with diseases involving the iliopsoas compartment (IPC) to assess the role of Ultrasound (US), Computed Tomography (CT) and Magnetic Resonance (MR) in the investigation of these deep seated and often clinically undetectable lesions. 16 (53%) patients had histologically proven benign or malignant IPC tumours with bacterial infection in 12 (40%) and haemorrhage into the IPC in 2 (7%). US correctly detected iliopsoas pathology in only 9 of 17 cases (53%) and was satisfactory only in limited situations, such as abscess formation in children and haemorrhage in haemophiliacs. CT was much more accurate (16/17, 94%) than US and correctly diagnosed 7 cases overlooked on US, while also offering greater information in 5 cases where both studies were abnormal. CT was particularly helpful for the detection of both abscess formation and calcification within mass lesion. MR was accurate in all 9 cases imaged, and was very helpful in the assessment of associated vertebral, disc or spinal canal involvement by tumour or infection. A review of the literature, and the results of this study, suggest that CT and MR often have complementary roles where IPC disease is known or suspected. The accuracy of US in IPC disease is limited, preferably being followed by CT or MR imaging.

[Cervical carcinoma staging with magnetic resonance tomography: the use of gadolinium-DOTA with 31 patients]

Thirty-one patients with histologically proven carcinoma of the cervix were studied by contrast-enhanced MRI. T2-weighted sequences in a spin-echo mode and T1-weighted sequences were carried out before and after the application of Gd-DOTA. This resulted in improved staging. Contrast-enhanced MRI provided valuable additional information concerning tumour extension into the parametrium. In the presence of motion artifacts and ill-defined infiltration into the parametrium on the T2 sequences, the use of contrast-enhanced T1 images provided a valuable addition to the investigation of carcinoma of the cervix.