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B Korf

Publications and source records attributed to B Korf.

At least 19 recordsLinked to original sources
PubMed2004

Phenotype characterization and natural history of spondylothoracic dysplasia syndrome: a series of 27 new cases.

Spondylothoracic dysplasia (STD, MIM#277300) is an autosomal recessive disorder with high prevalence in the Puerto Rican population. It is generally regarded as a lethal condition. Since Jarcho and Levin described it in 1938, it has been referred to as spondylocostal dysplasia, costovertebral dysplasia, Jarcho-Levin syndrome and STD. We have prospectively characterized 27 patients with STD by detailed physical examination, pedigree analysis, thoracic CT scans, and pulmonary function tests (PFTs). Diagnoses were established using spinal radiographs and 3-D reconstructive CT scans to demonstrate fusion of the ribs at the costo-vertebral junction with a fan-like (crab-like) configuration of the thorax. Vertebral segmentation and formation defects were seen throughout the spine with a decrease in the number of vertebral bodies. Characteristic vertebral shape consisted of a decrease in antero-posterior diameter and an increase in lateral length, giving the vertebra a sickle shape. Eight out of 18 prospectively follow patients died within the first 6 months of life, a 44% mortality rate. Cause of death was respiratory insufficiency secondary to pneumonia and pulmonary restriction. This is an important finding since the vast majority of STD syndrome patients cited in the medical literature have died in the newborn and early childhood periods. Age of the remaining patients ranged from 4 months to 47 years. This represents the largest collection of patients with STD reported and it has allowed us to determine a detailed phenotype. Given 56% survival at 6 months, we show that STD is not a lethal syndrome.

Abnormalities, Multiple↗
PubMed2003

Malignant peripheral nerve sheath tumours in neurofibromatosis type 1: MRI supports the diagnosis of malignant plexiform neurofibroma.

Plexiform neurofibroma (PNF) is a typical feature of neurofibromatosis 1 (NF1). About 10% of patients with NF1 develop malignant peripheral nerve-sheath tumours (MPNST), usually arising from PNF, and this is the major cause of poor survival. A better prognosis can be achieved if the tumours are diagnosed at an early stage. Our objective was to establish MRI criteria for MPNST and to test their usefulness in detecting early malignant change in PNF. MRI was performed on 50 patients with NF1 and nerve-sheath tumours, of whom seven had atypical pain, tumour growth or neurological deficits indicative of malignancy; the other 43 were asymptomatic. On MRI all seven symptomatic patients had inhomogeneous lesions, due to necrosis and haemorrhage and patchy contrast enhancement. In one patient, the multiplicity of confluent tumours with inhomogeneous areas in addition to central lesions did not allow exclusion of malignancy. Only three of the 43 asymptomatic patients had comparable changes; the other 40 patients had tumours being of relatively homogeneous structure on T1- and T2-weighted images before and after contrast enhancement. All three asymptomatic patients with inhomogeneous lesions were shown to have MPNST.

Adolescent↗
PubMed2002

Plexiform neurofibromas in NF1: toward biologic-based therapy.

Neurofibromatosis type 1 (NF1) is one of the most common neurogenetic diseases affecting adults and children. Neurofibromas are one of the most common of the protean manifestations of NF1. Plexiform neurofibromas, which will frequently cause cosmetic abnormalities, pain, and neurologic deficits, are composed of "neoplastic" Schwann cells accompanied by other participating cellular and noncellular components. There is increasing evidence that loss of NF1 expression in neoplastic Schwann cells is associated with elevated levels of activated RAS, supporting the notion that the NF1 gene product, neurofibromin, acts as a growth regulator by inhibiting ras growth-promoting activity. In addition, there is increasing evidence that other cooperating events, which may be under cytokine modulation, are important for neurofibroma development and growth. Treatment of plexiform neurofibromas has been empiric, with surgery being the primary option for those with progressive lesions causing a major degree of morbidity. The efficacy of alternative treatment approaches, including the use of antihistamines, maturation agents, and antiangiogenic drugs, has been questionable. More recently, biologic-based therapeutic approaches, using drugs that target the molecular genetic underpinnings of plexiform neurofibromas or cytokines believed important in tumor growth, have been initiated. Evaluation of such trials is hindered by the unpredictable natural history of plexiform neurofibromas and difficulties in determining objective response in tumors that are notoriously large and irregular in shape. Innovative neuroimaging techniques and the incorporation of quality-of-life scales may be helpful in evaluation of therapeutic interventions. The ability to design more rational therapies for NF1-associated neurofibromas is heavily predicated on an improved understanding of the molecular and cellular biology of the cells involved in neurofibroma formation and growth.

Biological Therapy↗
PubMed2001

Abdominal migraine in children with neurofibromatosis type 1: a case series and review of gastrointestinal involvement in NF1.

BACKGROUND: Symptomatic involvement of the gastrointestinal tract in children with neurofibromatosis type 1 (NF1) is rare. Most reported complications in adults are caused by the presence of neurofibromas in the stomach, small bowel, or mesentery. In contrast, abdominal pain in children with NF1 may be the result of nonanatomic causes, such as migraine. There are no previous reports of an association between abdominal migraine and NF1. METHODS: Children with abdominal migraine were identified from a group of children with NF1, all of whom had been followed up for a minimum of 3 years. Medical records of cases were reviewed independently by two authors. MEDLINE was searched via PubMed for all reports of children with NF1 and any associated gastrointestinal involvement. RESULTS: Six children with NF1 and intermittent, episodic, severe abdominal pain are reported. Investigations for obstructive or inflammatory causes of abdominal pain were negative. All patients had previously been diagnosed with migraine headaches by a neurologist. In five of the six patients, propranolol (10-15 mg three times daily) resulted in relief of their abdominal pain within days of starting therapy. Our review identified 24 children in the medical literature with gastrointestinal complications of NF1, mostly secondary to visceral neurofibromas. In almost all of these cases, clinical examination and simple radiologic investigations led to the definitive diagnosis. There were no reports of abdominal migraine complicating NF1. CONCLUSIONS: Abdominal pain secondary to migraine is an unrecognized cause of abdominal pain in children with NF1 and may be more common than anatomic causes of abdominal pain in children with NF1. In children with NF1 and severe recurrent abdominal pain in whom an evaluation for anatomic lesions is negative, a trial of migraine therapy may be indicated.

Abdominal Pain↗
PubMed1998

Identification of a novel genetic locus for familial cardiac myxomas and Carney complex.

BACKGROUND: Intracardiac myxomas are significant causes of cardiovascular morbidity and mortality through embolic stroke and heart failure. In the autosomal dominant syndrome Carney complex, intracardiac myxomas arise in the setting of lentiginosis and other lesions associated with cutaneous hyperpigmentation, extracardiac myxomas, and nonmyxomatous tumors. Genetic factors that regulate cardiac tumor growth remain unknown. METHODS AND RESULTS: We used the molecular genetic techniques of linkage analysis to study 4 kindreds affected by Carney complex to determine the genetic basis of this syndrome. Our investigation confirmed genetic heterogeneity of Carney complex. Moreover, genetic linkage analysis with polymorphic short tandem repeats on the long arm of chromosome 17 revealed maximal pairwise LOD scores of 5.9, 1.5, 1.8, and 2.9 for families YA, YB, YC01, and YC11, respectively. Haplotype analysis excluded a founder effect at this locus. These data identify a major 17 cM locus on chromosome 17q2 that contains the Carney complex disease gene. CONCLUSIONS: The ultimate identification and analysis of the Carney complex disease gene at this human chromosome 17q2 locus will facilitate diagnosis and treatment of cardiac myxomas and will foster new concepts in regulation of cardiac cell growth and differentiation.

Chromosomes, Human, Pair 17↗
PubMed1998

Genetic variation in the 3' untranslated region of the neurofibromatosis 1 gene: application to unequal allelic expression.

Neurofibromatosis type 1 (NF1) is a common genetic disorder caused by inactivation of neurofibromin, a protein capable of modulating signal transduction by activating Ras-GTPase activity. We have used cDNA cloning and Northern blot analysis to confirm the NF1 gene produces alternatively polyadenylated mRNAs with 3' untranslated regions (3' UTR) that show striking evolutionary conservation. Scanning of the 3'UTRs for genetic variation revealed three common sequence polymorphisms (> 30% heterozygosity), one less informative polymorphism (approximately 5% heterozygosity) and one rare variant (1/144 chromosomes). These differences were used to examine relative levels of expression of normal and mutant NF1 alleles in lymphoblast cell lines and in one case, autopsy tissue, from patients with NF1. Unequal allelic expression (up to 4-fold) was observed in a subset of both sporadic and familial NF1 cases. Where linkage phase could be determined, the allele segregating with the disorder displayed a relative reduction in expression. However, the magnitude of this effect was variable suggesting the operation of additional, non-genetic factors in determining the degree of relative expression of the mutant allele.

3' Untranslated Regions↗
PubMed1997

The diagnostic evaluation and multidisciplinary management of neurofibromatosis 1 and neurofibromatosis 2.

OBJECTIVE: Neurofibromatosis 1 and neurofibromatosis 2 are autosomal dominant genetic disorders in which affected individuals develop both benign and malignant tumors at an increased frequency. Since the original National Institutes of Health Consensus Development Conference in 1987, there has been significant progress toward a more complete understanding of the molecular bases for neurofibromatosis 1 and neurofibromatosis 2. Our objective was to determine the diagnostic criteria for neurofibromatosis 1 and neurofibromatosis 2, recommendations for the care of patients and their families at diagnosis and during routine follow-up, and the role of DNA diagnostic testing in the evaluation of these disorders. DATA SOURCES: Published reports from 1966 through 1996 obtained by MEDLINE search and studies presented at national and international meetings. STUDY SELECTION: All studies were reviewed and analyzed by consensus from multiple authors. DATA EXTRACTION: Peer-reviewed published data were critically evaluated by independent extraction by multiple authors. DATA SYNTHESIS: The main results of the review were qualitative and were reviewed by neurofibromatosis clinical directors worldwide through an Internet Web site. CONCLUSIONS: On the basis of the information presented in this review, we propose a comprehensive approach to the diagnosis and treatment of individuals with neurofibromatosis 1 and neurofibromatosis 2.

Genes, Neurofibromatosis 1↗
PubMed1997

Genetic heterogeneity of familial atrial myxoma syndromes (Carney complex).

Familial atrial myxomas may present as a component of the Carney complex, an autosomal dominant multiple neoplasia and lentiginosis syndrome. Although a gene defect for the Carney complex in some families maps to chromosome 2p, this syndrome is genetically heterogeneous, and other genetic loci also produce familial atrial myxomas.

Adult↗
PubMed1997

Limb anomalies in DiGeorge and CHARGE syndromes.

Limb anomalies are not common in the DiGeorge or CHARGE syndromes. We describe limb anomalies in two children, one with DiGeorge and the other with CHARGE syndrome. Our first patient had a bifid left thumb, Tetralogy of Fallot, absent thymus, right facial palsy, and a reduced number of T-cells. A deletion of 22q11 was detected by fluorescence in situ hybridization (FISH). The second patient, with CHARGE syndrome, had asymmetric findings that included right fifth finger clinodactyly, camptodactyly, tibial hemimelia and dimpling, and severe club-foot. The expanded spectrum of the DiGeorge and CHARGE syndromes includes limb anomalies.

Abnormalities, Multiple↗
PubMed1996

Allele-specific replication of 15q11-q13 loci: a diagnostic test for detection of uniparental disomy.

Allele-specific replication differences have been observed in imprinted chromosomal regions. We have exploited this characteristic of an imprinted region by using FISH at D15S9 and SNRPN (small nuclear ribonucleo protein N) on interphase nuclei to distinguish between Angelman and Prader-Willi syndrome patient samples with uniparental disomy of chromosome 15q11-q13 (n = 11) from those with biparental inheritance (n = 13). The familial recurrence risks are low when the child has de novo uniparental disomy and may be as high as 50% when the child has biparental inheritance. The frequency of interphase cells with asynchronous replication was significantly lower in patients with uniparental disomy than in patients with biparental inheritance. Within the sample population of patients with biparental inheritance, those with altered methylation and presumably imprinting center mutations could not be distinguished from those with no currently detectable mutation. This test is cost effective because it is performed on interphase cells from the same hybridized cytological preparation in which a deletion is excluded, and additional specimens are not required to determine the parental origin of chromosome 15.

Adult↗
PubMed1995

Preliminary phenotypic map of chromosome 4p16 based on 4p deletions.

We have collected and analyzed clinical information from 11 patients with chromosome 4p deletions or rearrangements characterized by various molecular techniques. Comparing the extent of these patients' deletions with their respective clinical presentations led to the proposal of a preliminary phenotypic map of chromosome 4p. This map consists of regions which, when deleted, are associated with specific clinical manifestations. Nonspecific changes such as mental and growth retardation are not localized, and probably result from the deletion of more than one gene or region. The region associated with most of the facial traits considered typical in Wolf-Hirschhorn syndrome (WHS) patients coincides with the currently proposed WHS critical region (WHSCR), but some anomalies commonly seen in WHS appear to map outside of the WHSCR. The observation of clinodactyly in 2 patients with nonoverlapping deletions allows assignment of these defects to at least 2 separate regions in 4p16. These initial observations and attempts at genotype/phenotype correlation lay the groundwork for identifying the genetic basis of these malformations, a common objective of gene mapping efforts and chromosome deletion studies.

Abnormalities, Multiple↗
PubMed1993

Interstitial deletion of distal chromosome 4p in a patient without classical Wolf-Hirschhorn syndrome.

We report on a patient with a de novo interstitial deletion of chromosome 4p; 46,XY,del(4) (p15.31p16.3). The cytogenetic diagnosis would predict a patient with the Wolf-Hirschhorn syndrome (WHS) since deletions of 4p16 are associated with WHS [Wilson et al., 1981]. This patient lacks the facial characteristics of WHS, but has some anomalies of WHS that are also commonly seen in other syndromes, i.e., severe growth retardation, developmental delay, and hypospadias. His molecular distal breakpoint occurs in 4p16.3 as defined by fluorescence in situ hybridization and Southern blot analysis, and his deletion does not overlap with the currently proposed WHS critical region. This case gives further support to the distal position of the WHS critical region and demonstrates some of the WHS associated phenotypes that can be attributed to a deletion of the proximal third of 4p16.3.

Blotting, Southern↗
PubMed1993

The Human Genome Project: implications for the practicing obstetrician.

The Human Genome Project is an international effort to discern the complete genetic makeup of human beings. The isolation and characterization of genes will offer tremendous opportunities for disease detection, diagnosis, screening, prevention, and counseling. Advances in genetic research are occurring simultaneously with the development of new techniques for prenatal genetic testing. Use of gene therapy in humans likely will lag behind our ability to detect genetic disorders. Consequently, obstetricians will be forced to face some difficult medical, ethical, and social challenges. The possibility of a national cystic fibrosis screening program is an example of the complex problems we will face as new genes are described. The obstetric community needs to participate actively in the debate surrounding the ethical and legal implications of the Human Genome Project. We need to establish clinical standards and use our professional organization to act as a resource for clinicians, the public, and legislatures. Because of the increased requirement for genetic counseling, we recommend an expansion of genetics training for residents and clinicians and the development of computer-based interactive video programs for genetic counseling.

Congenital Abnormalities↗