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Elizabeth Sweeney

Publications and source records attributed to Elizabeth Sweeney.

12 recordsLinked to original sources
PubMed2006

Molecular and clinical spectrum of type I plasminogen deficiency: A series of 50 patients.

Severe type I plasminogen (PLG) deficiency has been causally linked to a rare chronic inflammatory disease of the mucous membranes that may be life threatening. Here we report clinical manifestations, PLG plasma levels, and molecular genetic status of the PLG gene of 50 patients. The most common clinical manifestations among these patients were ligneous conjunctivitis (80%) and ligneous gingivitis (34%), followed by less common manifestations such as ligneous vaginitis (8%), and involvement of the respiratory tract (16%), the ears (14%), or the gastrointestinal tract (2%). Four patients showed congenital occlusive hydrocephalus, 2 with Dandy-Walker malformation of cerebellum. Venous thrombosis was not observed. In all patients, plasma PLG levels were markedly reduced. In 38 patients, distinct mutations in the PLG gene were identified. The most common genetic alteration was a K19E mutation found in 34% of patients. Transient in vitro expression of PLG mutants R134K, delK212, R216H, P285T, P285A, T319_N320insN, and R776H in transfected COS-7 cells revealed significantly impaired secretion and increased degradation of PLG. These results demonstrate impaired secretion of mutant PLG proteins as a common molecular pathomechanism in type I PLG deficiency.

Animals↗
PubMed2006

A molecular and clinical study of Larsen syndrome caused by mutations in FLNB.

BACKGROUND: Larsen syndrome is an autosomal dominant osteochondrodysplasia characterised by large-joint dislocations and craniofacial anomalies. Recently, Larsen syndrome was shown to be caused by missense mutations or small inframe deletions in FLNB, encoding the cytoskeletal protein filamin B. To further delineate the molecular causes of Larsen syndrome, 20 probands with Larsen syndrome together with their affected relatives were evaluated for mutations in FLNB and their phenotypes studied. METHODS: Probands were screened for mutations in FLNB using a combination of denaturing high-performance liquid chromatography, direct sequencing and restriction endonuclease digestion. Clinical and radiographical features of the patients were evaluated. RESULTS AND DISCUSSION: The clinical signs most frequently associated with a FLNB mutation are the presence of supernumerary carpal and tarsal bones and short, broad, spatulate distal phalanges, particularly of the thumb. All individuals with Larsen syndrome-associated FLNB mutations are heterozygous for either missense or small inframe deletions. Three mutations are recurrent, with one mutation, 5071G-->A, observed in 6 of 20 subjects. The distribution of mutations within the FLNB gene is non-random, with clusters of mutations leading to substitutions in the actin-binding domain and filamin repeats 13-17 being the most common cause of Larsen syndrome. These findings collectively define autosomal dominant Larsen syndrome and demonstrate clustering of causative mutations in FLNB.

Abnormalities, Multiple↗
PubMed2006

The origin of EFNB1 mutations in craniofrontonasal syndrome: frequent somatic mosaicism and explanation of the paucity of carrier males.

Craniofrontonasal syndrome (CFNS) is an X-linked disorder that exhibits a paradoxical sex reversal in phenotypic severity: females characteristically have frontonasal dysplasia, craniosynostosis, and additional minor malformations, but males are usually mildly affected with hypertelorism only. Despite this, males appear underrepresented in CFNS pedigrees, with carrier males encountered infrequently compared with affected females. To investigate these unusual genetic features of CFNS, we exploited the recent discovery of causative mutations in the EFNB1 gene, which encodes ephrin-B1, to survey the molecular alterations in 59 families (39 newly investigated and 20 published elsewhere). We identified the first complete deletions of EFNB1, catalogued 27 novel intragenic mutations, and used Pyrosequencing and analysis of nearby polymorphic alleles to quantify mosaic cases and to determine the parental origin of verified germline mutations. Somatic mosaicism was demonstrated in 6 of 53 informative families, and, of 17 germline mutations in individuals for whom the parental origin of mutation could be demonstrated, 15 arose from the father. We conclude that the major factor accounting for the relative scarcity of carrier males is the bias toward mutations in the paternal germline (which present as affected female offspring) combined with reduced reproductive fitness in affected females. Postzygotic mutations also contribute to the female preponderance, whereas true nonpenetrance in males who are hemizygous for an EFNB1 mutation appears unusual. These results highlight the importance of considering possible origins of mutation in the counseling of families with CFNS and provide a generally applicable approach to the combined analysis of mosaic and germline mutations.

Craniofacial Abnormalities↗
PubMed2006

Mutations in two regions of FLNB result in atelosteogenesis I and III.

The filamins are a family of cytoplasmic proteins that bind to and organize actin filaments, link membrane proteins to the cytoskeleton, and provide a scaffold for signaling molecules. Mutations in the gene encoding filamin B (FLNB) cause a spectrum of osteochondrodysplasias, including atelosteogenesis type I (AOI) and atelosteogenesis type III (AOIII). AOI and AOIII are autosomal dominant lethal skeletal dysplasias characterized by overlapping clinical findings that include vertebral abnormalities, disharmonious skeletal maturation, hypoplastic long bones, and joint dislocations. Previous studies have shown that heterozygosity for missense mutations that alter the CH2 domain and repeat 6 region of filamin B produce AOI and AOIII. In this study, 14 novel missense mutations in FLNB were found in 15 unrelated patients with AOI and AOIII. The majority of the mutations resided in exon 2 and exon 3, which encode the CH2 domain of the actin-binding region of filamin B. The remaining mutations were found in exon 28 and exon 29, which encode repeats 14 and 15 of filamin B. These results show that clustering of mutations in two regions of FLNB produce AOI/AOIII, and highlight the important role of this cytoskeletal protein in normal skeletogenesis.

Amino Acid Sequence↗
PubMed2006

Pfeiffer-type cardiocranial syndrome: a patient with features of this condition and with an unbalanced subtelomeric rearrangement involving chromosomes 1p and 17q.

Pfeiffer-type cardiocranial syndrome (MIM 218450) was first delineated in 1987; several further patients have been reported confirming this as a distinct nosological entity. The aetiology of this condition remains unknown although an autosomal recessive pattern of inheritance has been suggested following the description of sib pairs. A patient is described with features of this condition including sagittal suture synostosis, growth retardation, learning difficulties, hypertelorism, low-set ears, micrognathia, congenital heart defects and genital anomalies. Telomere studies on blood and skin samples identified a de novo unbalanced rearrangement resulting in partial monosomy for 1p36.1 to pter and partial trisomy for 17q25.1 to qter. This case provides the first insight into the possible aetiology of this condition.

Acrocephalosyndactylia↗
PubMed2005

Pontomedullary disconnection: fetal and neonatal considerations.

The cerebellar and pontocerebellar hypoplasias present a unique challenge when detected in the developing fetus. A diverse aetiology and prognosis make counselling of these families difficult. Advances in fetal imaging allow for more accurate diagnosis and counselling, but postnatal MRI is still required. A case is presented in which cerebellar hypoplasia was detected at 20 weeks gestation. Later fetal imaging provided further information, but a diagnosis of pontomedullary disconnection was not made until the postnatal MRI scan. The clinical findings and possible causes of such pontocerebellar abnormalities are discussed.

Abnormalities, Multiple↗
PubMed2005

A neurological phenotype in nail patella syndrome (NPS) patients illuminated by studies of murine Lmx1b expression.

Nail patella syndrome (NPS) is an autosomal dominant disorder affecting development of the limb, kidney and eye. NPS is the result of heterozygous loss-of-function mutations in the LIM-homeodomain transcription factor, LMX1B. Recent studies suggest that the NPS phenotype may be more extensive than recognized previously including neurologic and neurobehavioral aspects. To determine whether these findings correlated with the expression of Lmx1b during development, an internal ribosomal entry site-LacZ reporter was inserted into the 3'UTR of the endogenous murine gene. The pattern of Lmx1b expression during the development of the limb, eye and kidney correlates with the NPS phenotype. Additional sites of expression were observed in the central nervous system (CNS). The effects of the absence of Lmx1b in the CNS were determined in lmx1b-/- mice by histology and immunocytochemistry. Lmx1b is required for the differentiation and migration of neurons within the dorsal spinal cord. The inability of afferent sensory neurons to migrate into the dorsal horn is entirely consistent with diminished pain responses in NPS patients.

Animals↗
PubMed2004

The human LMX1B gene: transcription unit, promoter, and pathogenic mutations.

LMX1B is a LIM-homeodomain transcription factor required for the normal development of dorsal limb structures, the glomerular basement membrane, the anterior segment of the eye, and dopaminergic and serotonergic neurons. Heterozygous loss-of-function mutations in LMX1B cause nail patella syndrome (NPS). To further understand LMX1B gene regulation and to identify pathogenic mutations within the coding region, a detailed analysis of LMX1B gene structure was undertaken. 5' -RACE and primer extension identified a long 5' -untranslated region of 1.3 kb that contains two upstream open-reading frames (uORFs). Transient transfection assays showed that sequences required for basal promoter activity extend no further than 112 bp upstream. An additional 47 mutations have been identified in the coding region, as well as nine deletions of large portions of the gene, but not in the promoter or highly conserved intronic sequences. The range of mutations and the identification of uORFs suggest further complexity in the regulation of LMX1B expression.

Base Sequence↗
PubMed2002

A novel mutation in the IHH gene causes brachydactyly type A1: a 95-year-old mystery resolved.

Brachydactyly type A1 (BDA1) was the first disorder described in terms of autosomal dominant Mendelian inheritance. Early in the 1900s Farabee and Drinkwater described a number of families with BDA1. Examination of two of Drinkwater's families has revealed that, although they are not known to be related, both share a common mutation within the Indian hedgehog gene ( IHH). This novel mutation is a guanine to adenine transition at nucleotide 298, resulting in an Asn100Asp amino acid substitution. Both families demonstrate significant intrafamilial phenotypic heterogeneity among the affected individuals. Examination of single nucleotide polymorphisms (SNP) has shown that the affected individuals in both families share SNPs within IHH consistent with that of a common founder. The identification of the same mutation in these families has answered a question that is nearly a century old about the genetic cause of their disease and supports the hypothesis that IHH plays a pivotal role in normal human skeletogenesis.

Amino Acid Sequence↗
PubMed2002

Sotos syndrome: two cases with severe scoliosis.

Two patients with Sotos syndrome who developed a severe scoliosis are described. These cases illustrate the potential to develop significant spinal curvature in Sotos syndrome.

Age Determination by Skeleton↗
PubMed2002

Sacral appendage associated with a mutation in FGFR2.

We report a baby with craniosynostosis and a sacral appendage who has been found to have a Ser351Cys mutation in the fibroblast growth factor receptor 2 gene (FGFR2). This is the first report of sacral appendage associated with a confirmed mutation in one of the FGFR genes, and adds to the spectrum of abnormalities which can be seen in patients with FGFR mutations.

Craniosynostoses↗