Advances in genetics.
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Databases, Factual↗
Biomedical subjects
R M Winter
Publications and source records attributed to R M Winter.
The dysmorphic human-mouse homology database (DHMHD): an interactive World-Wide Web resource for gene mapping.
Genetic mapping and the examination of "candidate genes" for isolating loci associated with clinical syndromes can be greatly accelerated if there is information about where in the genome a particular locus might be situated. Such clues can come from homology to mouse mutants that have been mapped and knowledge of homology between mouse and human chromosomal segments. Further clues can come from chromosome aberrations giving a similar phenotype. However, these clues are often scattered widely in published reports, and even if they are collected together in catalogues or databases there is no rapid way of moving from one data type to another. The Dysmorphic Human and Mouse Homology Database (DHMHD) is designed to ease this data transition. DHMHD comprises detailed information from four separate sources and enables cross referencing through phenotypic and chromosome homology. The DHMHD system is a prototype which is now available online through the World-Wide Web.
Animals↗
A recurrent mutation, ala391glu, in the transmembrane region of FGFR3 causes Crouzon syndrome and acanthosis nigricans.
Mutations in the fibroblast growth factor receptor 2 (FGFR2) gene have previously been identified in Crouzon syndrome, an autosomal dominant condition involving premature fusion of the cranial sutures. Several different missense and other mutations have been identified in Crouzon syndrome patients, clustering around the third immunoglobulin-like domain. We report here the identification of a mutation in the transmembrane region of FGFR3, common to three unrelated patients with classical Crouzon syndrome and acanthosis nigricans, a dermatological condition associated with thickening and abnormal pigmentation of the skin. The mutation within the FGFR3 transcript was determined by direct sequencing as a specific gcg to gag transversion, resulting in an amino acid substitution ala391glu within the transmembrane region.
Acanthosis Nigricans↗
Spectrum of craniosynostosis phenotypes associated with novel mutations at the fibroblast growth factor receptor 2 locus.
The causative relationship between several of the syndromic forms of craniosynostosis and mutations in the fibroblast growth factor receptor (FGFR) loci is now well established. However, within the group of patients with craniosynostosis, there are several families and sporadic cases whose clinical features differ in variable degrees from the classically described syndromes of craniosynostosis. In this communication we present novel FGFR2 mutations associated with a spectrum of craniosyostosis phenotypes in 4 sporadic cases and in one family in which craniosynostosis segregates. The mutation and phenotype data presented emphasise the clinical variability of mutations at this locus and underline the plasticity of the phenotype-genotype relationship in this important group of congenital malformation syndromes. Mutations found were tyrosine 105 to cysteine, glycine 338 to glutamic acid, serine 351 to cysteine and glycine 384 to arginine. These are the first reported mutations in the first immunoglobulin-like loop (tyrosine 105 to cysteine) and the transmembrane domain (glycine 384 to arginine) of FGFR2, providing further insights into the mechanism of abnormal receptor function in FGFR2 mutations.
Craniosynostoses↗
Extreme intrauterine growth retardation, hydrocephalus and aged facial appearance: a previously unrecognized autosomal recessive disorder?
We present a boy with severe intrauterine growth retardation, relative macrocephaly, an aged appearance to the face, hydrocephaly and distinctive skeletal anomalies. Autosomal recessive inheritance is likely in view of the parental consanguinity.
Aging↗
Male pseudohermaphroditism in sibs with the alpha-thalassemia/mental retardation (ATR-X) syndrome.
Genital abnormalities have been noted in several patients with the X-linked form of alpha-thalassemia and mental retardation syndrome (ATR-X). The initial clinical report of the condition documented a phenotypic female with 46,XY karyotype. To this we now add 2 further siblings with abnormalities of the external genitalia, manifesting as male pseudohermaphroditism.
Abnormalities, Multiple↗
The molecular pathology of syndromic craniosynostosis.
Several monogenic disorders result in craniosynostosis, the premature fusion of skull sutures in the neonate, causing craniofacial malformation and, occasionally, neurological compromise. These malformations were initially classified on a clinical basis, but several recent reports have clarified the underlying mutations in many of these syndromes, allowing the complexity of the relationship between mutation and resultant phenotype to be viewed more clearly. This article summarizes the current situation regarding syndromic craniosynostosis, highlights the complementarity of clinical, cytogenetic and molecular approaches that have contributed to the improved understanding of the genetic basis of craniosynostosis, and considers the new challenges that have emerged.
Acrocephalosyndactylia↗
The detection of subtelomeric chromosomal rearrangements in idiopathic mental retardation.
A major challenge for human genetics is to identify new causes of mental retardation, which, although present in about 3% of individuals, is unexplained in more than half of all cases. We have developed a strategy to screen for the abnormal inheritance of subtelomeric DNA polymorphisms in individuals with mental retardation and have detected three abnormalities in 99 patients with normal routine karyotypes. Pulsed-field gel electrophoresis and reverse chromosome painting showed that one case arose from an interstitial or terminal deletion and two from the de novo inheritance of derivative translocation chromosomes. At least 6% of unexplained mental retardation is accounted for by these relatively small chromosomal abnormalities, which will be an important resource in the characterization of the genetic basis of neurodevelopment.
Adult↗
Identical mutations in the FGFR2 gene cause both Pfeiffer and Crouzon syndrome phenotypes.
Mutations in the fibroblast growth factor receptor 2 (FGFR2) gene have been identified in Crouzon syndrome, an autosomal dominant condition causing premature fusion of the cranial sutures (craniosynostosis). A mutation in FGFR1 has been established in several families with Pfeiffer syndrome, where craniosynostosis is associated with specific digital abnormalities. We now report point mutations in FGFR2 in seven sporadic Pfeiffer syndrome patients. Six of the seven Pfeiffer syndrome patients share two missense mutations, which have also been reported in Crouzon syndrome. The Crouzon and Pfeiffer phenotypes usually breed true within families and the finding of identical mutations in unrelated individuals giving different phenotypes is a highly unexpected observation.
Acrocephalosyndactylia↗
Mutations in the third immunoglobulin domain of the fibroblast growth factor receptor-2 gene in Crouzon syndrome.
Craniosynostosis, which affects approximately 1 in 2000 children, is the result of the abnormal development and/or premature fusion of the cranial sutures. Studies of mutations in patients with craniosynostosis have shown that the family of fibroblast growth factor receptor genes are extremely important in the correct formation of the skull, and digits. Mutations in the third immunoglobulin domain of fibroblast growth factor receptor 2 (FGFR2), in part of the molecule corresponding to a tissue specific isoform (IIIc), can cause both Crouzon and Pfeiffer syndromes. Two specific mutations in the linking region between the second and third immunoglobulin domains of FGFR2 occur in Apert syndrome. We present here mutations associated with the Crouzon syndrome, also in the third immunoglobulin domain but in an upstream exon. This exon is expressed in both tissue isoforms. Five different mutations were detected in 11 unrelated individuals. A cysteine to phenylalanine change was found in six individuals. This cysteine forms half of the disulphide bridge maintaining the secondary structure of the immunoglobulin domain. The first deletion within an FGFR gene is reported. Together with mutations in exon IIIc these account for 25 mutations out of 40 Crouzon patients studied in our combined series (5).
Amino Acid Sequence↗
Recent molecular advances in dysmorphology.
Recent advances in the mapping and isolation of genes responsible for birth defects are reviewed. Groups of disorders where rapid progress has been made include bone dysplasias, craniosynostoses and craniofacial syndromes.
Bone and Bones↗
Saethre-Chotzen syndrome associated with balanced translocations involving 7p21: three further families.
We describe three families segregating different reciprocal chromosome translocations, t(7;18)(p21.2;q23), t(2;7)(q21.1;p21.2), and t(5;7)(p15.3;p21.2). A total of seven apparently balanced carriers have been identified and all manifest features of the Saethre-Chotzen syndrome, although only two have overt craniosynostosis. In one family the carriers are immediately recognisable by their unusual ears, and clefts of the hard or soft palate are present in all three families. These observations extend previous linkage and cytogenetic evidence that a locus for Saethre-Chotzen syndrome resides in band 7p21.2.
Acrocephalosyndactylia↗
Alagille syndrome: family studies.
Alagille syndrome (AGS) is one of the major forms of chronic liver disease in childhood with severe morbidity and a mortality of 10 to 20%. It is characterised by cholestasis of variable severity with paucity of interlobular bile ducts and anomalies of the cardiovascular system, skeleton, eyes, and face. Previous studies suggest a wide variation in the expression of the disease and a high incidence of new mutations. To determine more accurately the rate of new mutations and to develop criteria for detecting the disorder in parents we systematically investigated parents in 14 families with an affected child. Clinical examination was supplemented by liver function tests, echocardiography, radiographic examination of the spine and forearm, ophthalmological assessment, and chromosome analysis. Six parents had typical anomalies in two or more systems pointing to the presence of autosomal dominant inheritance. Systematic screening of parents for the features defined in this study should improve the accuracy of genetic counselling.
Abortion, Spontaneous↗
Craniofacial abnormalities, agenesis of the corpus callosum, polysyndactyly and abnormal skin and gut development--the Curry Jones syndrome.
Five children are described with a striking, asymmetric facial appearance, craniosynostosis, preaxial polysyndactyly, agenesis of the corpus callosum and unusual skin with streaky areas of atrophy. The gut and mucous membranes are involved in two patients. This paper includes two patients described by Gorlin (1990) under the designation of the Curry Jones syndrome.
Abnormalities, Multiple↗
The natural history of human dermatosparaxis (Ehlers-Danlos syndrome type VIIC).
Dermatosparaxis (Ehlers-Danlos syndrome type VIIC) has only recently been identified in human subjects. Although well documented in animals, to date only three human cases have been recorded, all aged 2 years or under. We document a 15-year-old girl with this newly recognized condition to emphasize the remarkable similarity of physical signs in all four cases. The striking skin fragility which attends the phenotype is highly distinctive, so that the diagnosis may be suspected on clinical grounds. The confirmatory diagnostic procedures are discussed.
Adolescent↗
New autosomal dominant form of spondyloepiphyseal dysplasia presenting with atlanto-axial instability.
We present a family with a radiologically distinct new form of autosomal dominant spondyloepiphyseal dysplasia, presenting with cervical instability and attendant neurological compromise and emphasise the radiological characteristics which delineate this condition. Cervical vertebral abnormalities, including malformation of the odontoid process, have been observed in some forms of spondyloepiphyseal dysplasia, but rarely lead to neurological sequelae, in contrast to the pedigree we describe.
Atlanto-Axial Joint↗
Six cases of 7p deletion: clinical, cytogenetic, and molecular studies.
To date, 32 cases of partial 7p monosomy have been described, 14 of which have been associated with craniosynostosis (CRS). There is considerable variation in the size and location of the deleted segment. However, CRS appears to be consistently associated with either a deletion or partial deletion 7p21-->7p22 or more rarely a deletion of 7p13-->7p14. Analysis of a panel of six 7p deletion cases (three with CRS) was undertaken using informative DNA probes, in order to characterize and define the extent of the deletions at the molecular level. There were five de novo deletions and one resulting from the unbalanced product of a paternal balanced insertion. The putative proximal CRS locus at 7p13-->7p14 does not appear to be allelic with Greig cephalopolysyndactyly syndrome. Three probe positions have been refined: pJ5.11 (D7S10) previously mapped to 7p14-->pter does not appear to map proximal to p15; TM102L (D7S135) does not map distal to p22; CRI-P137 (D7S65) maps distal to 7p13.
Chromosome Banding↗
Pfeiffer syndrome.
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Abnormalities, Multiple↗