A new explanation for recessive myotonia congenita: exon deletions and duplications in CLCN1.

OBJECTIVE: To assess whether exon deletions or duplications in CLCN1 are associated with recessive myotonia congenita (MC). METHODS: We performed detailed clinical and electrophysiologic characterization in 60 patients with phenotypes consistent with MC. DNA sequencing of CLCN1 followed by multiplex ligation-dependent probe amplification to screen for exon copy number variation was undertaken in all patients. RESULTS: Exon deletions or duplications in CLCN1 were identified in 6% of patients with MC. Half had heterozygous exonic rearrangements. The other 2 patients (50%), with severe disabling infantile onset myotonia, were identified with both a homozygous mutation, Pro744Thr, which functional electrophysiology studies suggested was nonpathogenic, and a triplication/homozygous duplication involving exons 8-14, suggesting an explanation for the severe phenotype. CONCLUSIONS: These data indicate that copy number variation in CLCN1 may be an important cause of recessive MC. Our observations suggest that it is important to check for exon deletions and duplications as part of the genetic analysis of patients with recessive MC, especially in patients in whom sequencing identifies no mutations or only a single recessive mutation. These results also indicate that additional, as yet unidentified, genetic mechanisms account for cases not currently explained by either CLCN1 point mutations or exonic deletions or duplications.

Childhood predictive genetic testing for Li-Fraumeni syndrome.

Presymptomatic genetic testing in childhood for adult onset conditions is generally discouraged as it does not directly benefit the child and removes their autonomy. In certain cancer prone conditions such as Familial Adenomatous Polyposis and Von Hippel Lindau disease there are risks of disease in childhood and benefit to children not inheriting a mutation in being able to forego unpleasant screening tests. Li-Fraumeni syndrome caused by constitutional TP53 mutations there are also implications in childhood with a risk of around 20% of a childhood malignancy. However, as yet no evidence based surveillance programme has been identified. We describe our experience of childhood testing for four children in two Li-Fraumeni families caused by TP53 mutations.

Hopping hotspots: global shifts in marine biodiversity.

Hotspots of high species diversity are a prominent feature of modern global biodiversity patterns. Fossil and molecular evidence is starting to reveal the history of these hotspots. There have been at least three marine biodiversity hotspots during the past 50 million years. They have moved across almost half the globe, with their timing and locations coinciding with major tectonic events. The birth and death of successive hotspots highlights the link between environmental change and biodiversity patterns. The antiquity of the taxa in the modern Indo-Australian Archipelago hotspot emphasizes the role of pre-Pleistocene events in shaping modern diversity patterns.

Mosaicism in autosomal dominant polycystic kidney disease revealed by genetic testing to enable living related renal transplantation.

Patients with end-stage renal disease (ESRD) secondary to autosomal dominant polycystic kidney disease (ADPKD) receive fewer living-related kidney (LRK) transplants than other groups with ESRD. This relates to the difficulties in excluding the disease in potential donors. We report a case which highlights these difficulties and, by discovery of mosaicism for a new mutation, illustrates the role of clinical and molecular genetic resources in assessing young related kidney donors for patients with ADPKD.

22q11 deletion: a multisystem disorder requiring multidisciplinary input.

AIM: To draw up recommendations for the investigation and management of children with a microdeletion of chromosome 22q11. METHODS: A retrospective review of case notes from patients with a chromosome 22q11 microdeletion identified by cytogenetics laboratories of the south and west of Britain over a four year period. RESULTS: A total of 210 cases were identified. Age at diagnosis was 0-1 years (34%), 1-4 (17%), 5-17 (35%), and 18 years or more (13%). School age children were less likely to be investigated than infants: echocardiography in school age 86% v in infancy 97%, serum calcium 66% v 89%, renal ultrasound scan 38% v 42%, lymphocyte count 26% v 68%, parental karyotype 78% v 88%. The yield of investigations remained high throughout all age groups with 42% of school age children shown to have hypocalcaemia and 25% abnormal findings on renal ultrasound. CONCLUSIONS: 22q11 microdeletion is a multisystem disorder requiring a set of core investigations at diagnosis. We recommend an echocardiogram, renal ultrasound scan, lymphocyte count and function, serum calcium, and parental karyotype as a minimum. Genetic counselling and community paediatric input is helpful for most families.

Siblings with Bohring-Opitz syndrome.

We describe a brother and sister with Bohring-Opitz syndrome and suggest that autosomal recessive inheritance may occur in this condition.

Mutations in the general transcription factor TFIIH result in beta-thalassaemia in individuals with trichothiodystrophy.

The transcription factor TFIIH is involved in both basal transcription and DNA repair. Mutations in the XPD helicase component of TFIIH can result in the diverse clinical features associated with xeroderma pigmentosum (XP) and trichothiodystrophy (TTD). It is generally believed that the multi-system abnormalities associated with TTD are the result of a subtle deficiency in basal transcription. However, to date, there has been no clear demonstration of a defect in expression of any specific gene in individuals with these syndromes. Here we show that the specific mutations in XPD that cause TTD result in reduced expression of the beta-globin genes in these individuals. Eleven TTD patients with characterized mutations in the XPD gene have the haematological features of beta-thalassaemia trait, and reduced levels of beta-globin synthesis and beta-globin mRNA. All these parameters were normal in three patients with XP. These findings provide the first evidence for reduced expression of a specific gene in TTD. They support the hypothesis that many of the clinical features of TTD result from inadequate expression of a diverse set of highly expressed genes.

Classification and genetic features of neonatal haemochromatosis: a study of 27 affected pedigrees and molecular analysis of genes implicated in iron metabolism.

Neonatal haemochromatosis (NH) is a severe and newly recognised syndrome of uncertain aetiology, characterised by congenital cirrhosis or fulminant hepatitis and widespread tissue iron deposition. NH occurs in the context of maternal disease including viral infection, as a complication of metabolic disease in the fetus, and sporadically or recurrently, without overt cause, in sibs. Although an underlying genetic basis for NH has been suspected, no test is available for predictive analysis in at risk pregnancies. As a first step towards an understanding of the putative genetic basis for neonatal haemochromatosis, we have conducted a systematic study of the mode of transmission of this disorder in a total of 40 infants born to 27 families. We have moreover carried out a molecular analysis of candidate genes (beta(2)-microglobulin, HFE, and haem oxygenases 1 and 2) implicated in iron metabolism. No pathogenic mutations in these genes were identified that segregate consistently with the disease phenotype in multiplex pedigrees. However, excluding four pedigrees with clear evidence of maternal infection associated with NH, a pedigree showing transmission of maternal antinuclear factor and ribonucleoprotein antibodies to the affected infants, and two families with possible matrilineal inheritance of disease in maternal half sibs, a large subgroup of the affected pedigrees point to the inheritance of an autosomal recessive trait. This included 14 pedigrees with affected and unaffected infants and a single pedigree where all four affected infants were the sole offspring of consanguineous but otherwise healthy parents. We thus report three distinct patterns of disease transmission in neonatal haemochromatosis. In the differentiation of a large subgroup showing transmission of disease in a manner suggesting autosomal recessive inheritance, we also provide the basis for further genome wide studies to define chromosomal determinants of iron storage disease in the newborn.

Cerebrospinal fluid cytokine levels after surgery with spinal or general anesthesia.

BACKGROUND AND OBJECTIVES: Studies show that pain may cause neuroinflammatory changes in the spinal cord. These inflammatory changes could be caused by circulating factors such as plasma cytokines or could be a primary neuroimmune response of the central nervous system following peripheral nerve injury. To identify the possible effects of peripheral trauma and pain on the cytokine environment of the spinal cord, interleukin-6 (IL-6) and interleukin-10 (IL-10) concentrations in plasma and cerebrospinal fluid (CSF) were measured before and after hip replacement surgery. METHODS: The investigation used a prospective, observational design to measure cytokine levels in samples of plasma and CSF by enzyme-linked immunosorbent assay (ELISA). Samples were taken from surgical patients before and after surgery under general anesthesia or spinal anesthesia performed with or without a spinal catheter. Reference samples were also obtained from healthy control subjects. RESULTS: Both plasma and CSF levels of IL-6 increased substantially after major surgery with either general or spinal anesthesia. No significant correlation was observed between plasma IL-6 and CSF IL-6 levels, suggesting a central origin for increased CSF cytokine levels. IL-10 did not change in plasma or CSF after surgery. Plasma and CSF IL-6 and IL-10 cytokine levels were very low or undetectable in healthy controls. CONCLUSIONS: Major orthopedic surgery leads to elevated CSF levels of the proinflammatory cytokine, IL-6. The origin of increased CSF IL-6 may be central because there was no significant correlation with plasma levels.

Genetic analysis of the G4.5 gene in families with suspected Barth syndrome.

Mutations have recently been identified in the G4.5 gene (Xq28), encoding the tafazzin protein, in patients with Barth syndrome. We performed mutational analysis in 5 families with suspected Barth syndrome. In 4 families a male child had all the cardinal features of this syndrome, and mutations of G4.5 were found in each case. A mutation was also found in a fifth family with an extensive history of early infant death from heart disease. The recognition of 5 unrelated families in 1 hospital during a 7-year period suggests that this disease may be underdiagnosed.

The state of implantable pain therapies in the United States: a nationwide survey of academic teaching programs.

UNLABELLED: The purpose of this questionnaire survey was to provide an overview of anesthesiology pain fellowship programs in the United States with regard to implantation of spinal cord stimulators (SCS) and opioid infusion devices. Of the 95 programs solicited, 80% responded to questions pertaining to the prevalence of use and technical considerations of implantation. Of the responding programs, 87% report implanting SCS, and 84% report implanting neuraxial infusion pumps. All programs perform a stimulation or infusion trial before implantation, although the duration varied from a trial in the operating room at the time of implantation to 25 days. Of the programs, 83% implant cylindrical leads, and 17% implant flat leads via laminectomy for their nonrevision SCS implants. Morphine, bupivacaine, hydromorphone, and baclofen are the most commonly used drugs and are used in implanted pumps by >50% of respondents. The question of industry-sponsored pain fellow education in implantable techniques is addressed. IMPLICATIONS: Of the pain teaching programs in the United States, 80% responded to a questionnaire eliciting information about the implantation of spinal cord-stimulating and opioid infusion devices. The range and diversity of responses imply a lack of agreement about implantation techniques, drugs, and protocols.

The Opitz syndrome gene product, MID1, associates with microtubules.

Opitz syndrome (OS) is a genetically heterogeneous disorder characterized by defects of the ventral midline, including hypertelorism, cleft lip and palate, heart defects, and mental retardation. We recently identified the gene responsible for X-linked OS. The ubiquitously expressed gene product, MID1, is a member of the RING finger family. These proteins are characterized by an N-terminal tripartite protein-protein interaction domain and a conserved C terminus of unknown function. Unlike other RING finger proteins for which diverse cellular functions have been proposed, the function of MID1 is as yet undefined. By using the green fluorescent protein as a tag, we show here that MID1 is a microtubule-associated protein that influences microtubule dynamics in MID1-overexpressing cells. We confirm this observation by demonstrating a colocalization of MID1 and tubulin in subcellular fractions and the association of endogenous MID1 with microtubules after in vitro assembly. Furthermore, overexpressed MID1 proteins harboring mutations described in OS patients lack the capability to associate with microtubules, forming cytoplasmic clumps instead. These data give an idea of the possible molecular pathomechanism underlying the OS phenotype.

Prenatal onset spinal muscular atrophy.

Five patients with severe spinal muscular atrophy (SMA) type I, all of whom presented with reduced fetal movements in utero, severe weakness at birth, and short survival time were assessed to attempt to determine whether their phenotype could be explained by their genotype. The diagnosis was confirmed by clinical, electrophysiological and histopathological features. Polymerase chain reaction assays were used to define the molecular diagnosis. A gene-dosage assay was used to assess the quantity of centromeric survival motor neuron gene (SMNc) present. In all cases the telomeric survival motor neuron gene (SMNt) was absent. The SMNc gene was present but in reduced copy number compared with a control group of children with less severe type I SMA, so may be important in determining severity. In the differential diagnosis of reduced fetal movements, SMA should be considered. The clinical classification may in future be clarified by molecular genetic findings.

Improved molecular diagnosis of facioscapulohumeral muscular dystrophy (FSHD): validation of the differential double digestion for FSHD.

A major advance in the molecular diagnosis of facioscapulohumeral muscular dystrophy is the recently reported elimination of confounding DNA fragments arising from homologous sequences located at 10q26. In order to evaluate the specificity and sensitivity of this important diagnostic test, we have compared a group of 130 patients fulfilling the diagnostic criteria for FSHD with 200 control subjects not known to have an increased risk of having an FSHD mutation. Among the FSHD cases the smallest BlnI/EcoRI fragment sizes ranged from 10 to > 48 kb with 94.6% (95% CI 89.2-97.8%) of cases having fragment sizes of 34 kb or less. Among the 400 chromosomes from controls the smallest BlnI/EcoRI fragment observed with the EcoRI/BlnI double restriction enzyme digest was 38 kb +/- 2 kb, suggesting a test specificity at a fragment size < 34 kb of or very near to 100% (lower 95% CI 98.2%). Test sensitivity at < 34 kb is estimated at 94.6% (95% CI 89.2-97.8%), all outliers having fragments > 38 kb. The Southern blot analysis with DNA probe p13E-11 has created a valuable molecular diagnostic test for FSHD.

Nephrogenic rests and renal abnormalities in Brachmann-de Lange syndrome.

We report renal abnormalities found in four cases of Brachmann-de Lange syndrome (BDLS). In two there were nephrogenic tests and renal cortical cysts, a further case showed cortical cysts, and the fourth had dilated collecting ducts. The literature describing renal abnormalities in BDLS has been reviewed, and this includes a report of one individual with BDLS who developed Wilms tumor. The genetic basis of BDLS has not been elucidated, although a submicroscopic abnormality of chromosome 3 seems likely. Nephrogenic rests may be Wilms' tumor precursor lesions and are seen in syndromes associated with Wilms' tumors. Mutations of genes on chromosome 11 are the most common genetic abnormalities associated with Wilms' tumor, but other chromosomes have also been implicated. The frequency of renal abnormalities in the BDLS suggests that the involved gene may be important in renal development and also possibly in Wilms' tumors.