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C S Munro

Publications and source records attributed to C S Munro.

At least 55 records · Page 3Linked to original sources
PubMed1998

Refined genetic mapping of the darier locus to a <1-cM region of chromosome 12q24.1, and construction of a complete, high-resolution P1 artificial chromosome/bacterial artificial chromosome contig of the critical region.

Darier disease (DD) (MIM 124200) is an autosomal dominant skin disorder characterized by loss of adhesion between epidermal cells and by abnormal keratinization. We present linkage analysis showing, in four families, key recombination events that refine the location of the DD locus on chromosome 12q23-24.1 to a region of <1 cM. We have constructed a YAC/P1 artificial chromosome (PAC)/bacterial artificial chromosome (BAC)-based physical map that encompasses this refined DD region. The map consists of 35 YAC, 69 PAC, 16 BAC, and 2 cosmid clones that were ordered by mapping 54 anonymous sequence-tagged sites. The critical region is estimated to be 2.4 Mb in size, with an average marker resolution of 37.5 kb. The refinement of the critical interval excludes the ALDH2, RPL6, PTPN11, and OAS genes, as well as seven expressed sequence tags (ESTs) previously mapped in the DD region. The three known genes (ATP2A2, PPP1CC, and SCA2) and the 10 ESTs mapped within the critical region are not obvious candidates for the DD gene. Therefore, this detailed integrated physical, genetic, and partial transcript map provides an important resource for the isolation of the DD gene and, possibly, other disease genes.

Chromosome Mapping↗
PubMed1997

Missense mutations in keratin 17 cause either pachyonychia congenita type 2 or a phenotype resembling steatocystoma multiplex.

Pachyonychia congenita (PC) is a group of autosomal dominant ectodermal dysplasias in which the main phenotypic characteristic is hypertrophic nail dystrophy. In the Jackson-Lawler form (PC-2), pachyonychia is accompanied by multiple pilosebaceous cysts, natal teeth, and hair abnormalities. By direct sequencing of genomic PCR products, we report heterozygous K17 missense mutations in the same conserved protein motif in a further five PC-2 families (K17 N92S in one familial and three sporadic cases; K17 Y98D in one familial case) confirming that mutations in this gene are a common cause of PC-2. We also show heterozygous missense mutations in K17 (N92H and R94H) in two families diagnosed as steatocystoma multiplex. Mild nail defects were observed in some but not all of these patients on clinical re-evaluation of these families. All the K17 mutations reported here were shown to co-segregate with the disease in the pedigrees analyzed and were excluded from 100 unaffected, unrelated chromosomes by restriction enzyme analysis of K17 genomic PCR products. We conclude that phenotypic variation is observed with K17 mutations, as is the case with other keratin disorders.

Cysts↗
PubMed1997

Loricrin mutation in Vohwinkel's keratoderma is unique to the variant with ichthyosis.

A mutation in the glycine-rich cornified envelope protein loricrin has recently been reported in Vohwinkel's keratoderma (honeycomb keratoderma with pseudoainhum), in a pedigree amongst whom ichthyosis was also a feature. We have studied two further families with Vohwinkel's keratoderma for evidence ofloricrin mutations. Our first family (VK1) also had ichthyosis but not deafness. In lesional and nonlesional skin, granular and transitional cell layers were increased. In immunoelectron-microscopic studies cornified envelopes were abnormally thin and were labeled densely by anti-involucrin antibodies, but only sparsely by antiloricrin antibodies; however, abnormal intranuclear granules seen in granular and cornified layer cells were labeled by antibodies to both C- and N-terminal loricrin. Microsatellite markers in VK1 supported linkage to the loricrin locus in the epidermal differentiation complex at 1q21 (Zmax = 2.48). The loricrin gene was sequenced, identifying a heterozygous mutation as previously reported: a G insertion producing a frameshift after codon 231 and an abnormal C-terminal peptide lacking residues necessary for cross-linking. In our second family (VK2), affected members had sensorineural deafness but not ichthyosis. Immunoelectron-microscopic studies showed normal loricrin distribution, and assuming complete penetrance, linkage to 1q21 was excluded. Vohwinkel's keratoderma is thus clinically and genetically heterogeneous. Only the variant with ichthyosis appears to be due to loricrin mutation. As the arginine-rich domain in C-terminal loricrin caused by the frameshift contains several potential bipartite nuclear localization signals, we suggest that the intranuclear accumulation of loricrin in VK1 is due to these motifs, and may be unique to insertional mutation.

Adolescent↗
PubMed1997

Systemic lupus erythematosus complicating complement type 2 deficiency: successful treatment with fresh frozen plasma.

We report a man who presented in 1981 at the age of 30 with cutaneous lupus erythematosus (LE), which was resistant to a range of treatments over the subsequent 11 years. In 1991 he suffered fits, dysphasia and agitated depression, and in 1992 a severe septicaemic illness. Systemic LE was diagnosed, and investigation showed homozygous complement type 2 deficiency (C2d). Over a period of 30 months he has received 6 weekly fresh frozen plasma. Since starting this treatment his cutaneous disease has resolved and his depression, verbal fluency and psychomotor scores improved. We have not observed any adverse effects to this treatment and suggest it should be considered in similar patients.

Adult↗
PubMed1997

Treatment of psoriasis with intermittent short course cyclosporin (Neoral). A multicentre study.

A 1 year, prospective multicentre study was performed to investigate the efficacy and safety of intermittent treatment with cyclosporin in psoriasis vulgaris. Subjects received cyclosporin (Neoral) 5 mg/kg per day until achieving 90% reduction in area affected, or for a maximum of 12 weeks. Those failing to demonstrate a satisfactory response were withdrawn. When further treatment was required, cyclosporin was recommenced. This cycle was repeated up to three times. Psoriasis activity was recorded using the area affected and sign scores for erythema, scaling and infiltration. Overall assessments of response and tolerability were recorded. Forty-one subjects, mean age 36, mean PASI 12.8, entered the first treatment period. Thirty-three received a second period of treatment and 16 a third. Eighteen failed to complete the study as planned: five were withdrawn due to adverse events, four due to treatment failure and nine due to protocol violations. At the end of each treatment period, significant improvements were seen in all efficacy parameters. Overall response was graded as 'considerable improvement' or 'minimal or no symptoms', by over 80% of subjects and investigators. Median intervals to relapse for subjects remaining in the study were 72 days (range 28-329) and 53 days (range 14-141) after periods 1 and 2, respectively. There were significant increases in mean serum creatinine and blood pressure during each treatment period. However, there were no significant differences in either parameter between baseline and the final follow-up visit. At the end of each treatment period, overall tolerability of the treatment was considered 'good' or 'very good' by over 80% of subjects and investigators.

Adult↗
PubMed1995

A mutation in the mucosal keratin K4 is associated with oral white sponge nevus.

White sponge nevus (WSN) is a benign autosomal dominant disorder which affects non-cornifying stratified squamous epithelia (MIM 193900) (ref. 1). Phenotypically it presents as white 'spongy' plaques (oral leukokeratoses), most commonly in the mouth but also reported in the esophagus and anogenital mucosa. Histologically, the plaques show evidence of hyperproliferation, acanthosis and tonofilament aggregation. These types of pathogenic changes are characteristic of many of the epidermal keratin disorders. Keratins are expressed in pairs by epithelial cells in a tissue and cell specific manner. The major differentiation specific keratins of the buccal mucosa, nasal, esophageal and anogenital epithelia are K4 and K13 (ref. 7). The tissue distribution and nature of the lesions in patients affected by WSN suggested that mutations in K4 and/or K13 might be responsible for this disorder. We have now confirmed this hypothesis and report here a three base-pair (bp) deletion in the helix initiation peptide of K4 in affected members from two families with this condition.

Amino Acid Sequence↗
PubMed1995

A gene for monilethrix is closely linked to the type II keratin gene cluster at 12q13.

Monilethrix is an uncommon hereditary disorder of hair and nail which produces hair fragility and a variable alopecia. Many of the dystrophic hairs have a unique beaded morphology. Ultrastructural changes suggest a defect in the microfilament structure of the cortex of the hair shaft,and hence the cysteine-rich trichocyte keratins are candidate genes. Here, in two families with autosomal dominant monilethrix, we have excluded linkage to the type I keratin gene cluster on chromosome 17q, but show that the disorder is closely linked to the type II keratin cluster on 12q, where genes for basic trichocyte keratins are found. The combined maximum lod score for D12S96 was 12.27 at theta=0.0. This is the first mapping of a primary human hair disorder and the first evidence implicating a defect of the word 'hard' keratins of hair and nail disease.

Chromosomes, Human, Pair 12↗
PubMed1995

Remission of ordinary psoriasis following a short clearance course of cyclosporin.

We set out to show that the assumption is incorrect that continuous treatment with cyclosporin is necessary in psoriasis, as this tenet forms a basis for current recommended treatment regimens. Sixty patients with mild to moderate plaque psoriasis were allocated at random to treatment with oral cyclosporin 5 mg/kg/day (30 patients) or topical dithranol and ultraviolet B therapy (30 patients) for up to 16 weeks until clear (median time 6 weeks cyclosporin and 8 dithranol), and the times to relapse compared. The patients were seen monthly for up to 8 months, and the severity and the extent of psoriasis were assessed. Relapse, defined as return of psoriasis to 50% of the area at the start of the trial or patient demand for further treatment, was not significantly different between the groups (hazard ratio 1.11, 95% CI 0.55-2.32). No patients suffered a rebound of severe disease and none relapsed in the first 8 weeks after stopping treatment. The relapse rate was higher following cyclosporin from 8 to 28 weeks after treatment and following dithranol from 28 to 34 weeks. The patients with arthritis had a higher median joint severity score at relapse than prior to treatment with cyclosporin. At the end of 8 months, 5 patients treated with dithranol and 8 patients with cyclosporin remained clear, 75% and 67% having relapsed. We conclude that rapid relapse does not occur after clearance of mild to moderate plaque psoriasis with cyclosporin and the relapse rate was no different from dithranol treatment.

Administration, Oral↗
PubMed1994

Linkage analyses in British pedigrees suggest a single locus for Darier disease and narrow the location to the interval between D12S105 and D12S129.

Darier disease is a dominantly inherited skin disorder in which there appears to be abnormal adhesion between keratinocytes. We and others have shown that the disease in some British pedigrees is closely linked to markers mapping to 12q23-q24.1. In the present study we have defined crossovers that enable us to narrow the location of the disease gene to the interval between the D12S105 and the D12S129 markers. This interval may be expected to be on the order of about 4 cM on the basis of linkage data obtained using the primary CEPH reference families. Our data provide further evidence for locus homogeneity: each of four large British pedigrees, two of which have previously been subjected to preliminary characterization, shows statistically significant evidence for linkage to markers mapping to 12q23-q24.1.

Chromosome Mapping↗
PubMed1994

Maintenance treatment with cyclosporin in atopic eczema.

We have studied two reducing-dose regimens intended to minimize toxicity of cyclosporin A (CyA) while maintaining its capacity to control atopic eczema following induction of remission. Twenty-four patients with severe chronic atopic eczema were first treated in a double-blind randomized placebo-controlled cross-over study of CyA (5 mg/kg/day). All 19 who completed the study showed the expected highly significant improvements, compared with placebo, in area involved, erythema, excoriation, lichenification, itch and requirement for topical steroid. In 17 of the 19 patients, control was re-established with CyA 5 mg/kg/day, and they were then re-randomized to stepwise reduction at 2-week intervals in either (i) the dose of CyA given daily, or (ii) the frequency with which the 5 mg/kg dose was given. Fifteen patients (seven continuous reducing dose, eight intermittent fixed dose) completed the planned reduction to either 1 mg/kg/day or 5 mg/kg every fifth day. In both groups the response was sustained despite dose reduction, although control was less good at a continuous dose of 1 mg/kg. Intermittent treatment was as good as or better than continuous reducing dosage in this study, and in both groups there was further deterioration after the drug was stopped. The findings suggest that the dose of CyA required to control atopic eczema is less than that required to achieve remission, and that the therapeutic index can be further improved by alternative dosing strategies. This offers a new approach to maintenance treatment of eczema and other chronic refractory dermatoses.

Adult↗
PubMed1994

A gene for pachyonychia congenita is closely linked to the keratin gene cluster on 17q12-q21.

Pachyonychia congenita (PC) is a group of hereditary syndromes which have in common a hypertrophic dystrophy of the distal nail, and are associated with a variety of additional features, notably various dyskeratoses of skin and mucous membranes. The pathology is unknown but the array of clinical features suggests the possibility of a keratin abnormality. In the present report we describe linkage analyses in a large PC pedigree of the Jackson-Lawler type, a subtype which is characterised by multiple epidermal cysts, hair abnormalities, and natal teeth. The disease locus in this family was found to be tightly linked to markers mapping within, or very close to, the keratin type I cluster at 17q12-q21; maximum lod scores for linkage of the disease to a KRT10 polymorphism and to D17S800, a marker known to be very tightly linked to KRT10, were respectively +4.51 and +7.73, both at theta = 0.00. Although always likely, our findings provide strong evidence of a keratin gene anomaly underlying an inherited disorder affecting epidermis, nail, hair, and mucosa. These findings permit testing to see if pachyonychia congenita shows any locus heterogeneity and suggest specific candidate keratin genes for mutation searching studies. In addition, they suggest a role for keratins in the phenomenon of natal dentition.

Chromosomes, Human, Pair 17↗
PubMed1994

Symptomatic and asymptomatic salivary duct abnormalities in Darier's disease: a sialographic study.

Symptoms of obstructive sialadentis have been occasionally reported as a feature of Darier's disease. Parotid sialograms of three patients with confirmed Darier's disease and histories suggestive of salivary obstruction revealed dilatation with periodic strictures and indentations affecting the main ducts. Similar parotid sialograms in three Darier's disease patients with no symptoms attributable to their salivary glands revealed seepage of contrast media associated with the secondary and tertiary ducts. These findings suggest that salivary glands may be more commonly involved in Darier's disease than previous reports indicate.

Adolescent↗
PubMed1992

The phenotype of Darier's disease: penetrance and expressivity in adults and children.

The prevalence, pattern of inheritance, and phenotype of Darier's disease was examined in a cross-sectional study of cases in north-east England. Seventy-five cases, representing a local prevalence of at least 1:36,000, were identified and examined. Forty-two cases were known to dermatologists, and 33 were identified in the course of the study: 60 were adults (above the age of 20) and 15 were children. In nine families, 66 of 136 adults with an affected parent were known to be affected, indicating complete penetrance of an autosomal dominant gene. eighteen individuals gave no family history, but seven of these were found to be members of affected kindreds and five obligate carriers examined all proved to have evidence of the disease. In other 'new' cases, including several whose parents were examined and confirmed to be normal, no relationship to other cases was found. These cases probably represent new mutations or non-paternity rather than incomplete penetrance. All but one adult case had the typical rash, but it was milder in women; 16/18 adults who had not presented to dermatologists were female. Diagnostic nail lesions were found in 59 (99%), palmar pits and keratoses in 57 (95%), and acrokeratosis verruciformis in 44 (73%). In 15 young cases (aged 5-18) with one or more diagnostic features, the rash was found in only four (27%), nail lesions in nine (60%), palmar pits in eight (53%), and acrokeratoses in ten (67%). The minor lesions were often subtle but were more consistent early evidence of disease than the rash, and even in the absence of a rash gene penetrance may be complete by the age of 10.

Adolescent↗
PubMed1992

An acantholytic dyskeratotic epidermal naevus with other features of Darier's disease on the same side of the body.

Many epidermal naevi with the histology of Darier's disease have been reported. In the absence of associated features of Darier's disease, they cannot be assumed to have a common pathogenesis with it, and it has been suggested that they are better classified as acantholytic dyskeratotic epidermal naevi rather than naevoid Darier's disease. We describe a patient with such a naevus who had typical nail and palmar changes of Darier's disease on the same side of the body. We suggest that in at least some cases the naevus has the same genetic defect(s) as generalized Darier's disease, and discuss the possibility that a patient with such a naevus could occasionally transmit Darier's disease to an offspring.

Adult↗