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C R Greenberg

Publications and source records attributed to C R Greenberg.

At least 19 recordsLinked to original sources
PubMed2007

Guideline for the diagnosis and management of glutaryl-CoA dehydrogenase deficiency (glutaric aciduria type I).

Glutaryl-CoA dehydrogenase (GCDH) deficiency is an autosomal recessive disease with an estimated overall prevalence of 1 in 100 000 newborns. Biochemically, the disease is characterized by accumulation of glutaric acid, 3-hydroxyglutaric acid, glutaconic acid, and glutarylcarnitine, which can be detected by gas chromatography-mass spectrometry of organic acids or tandem mass spectrometry of acylcarnitines. Clinically, the disease course is usually determined by acute encephalopathic crises precipitated by infectious diseases, immunizations, and surgery during infancy or childhood. The characteristic neurological sequel is acute striatal injury and, subsequently, dystonia. During the last three decades attempts have been made to establish and optimize therapy for GCDH deficiency. Maintenance treatment consisting of a diet combined with oral supplementation of L: -carnitine, and an intensified emergency treatment during acute episodes of intercurrent illness have been applied to the majority of patients. This treatment strategy has significantly reduced the frequency of acute encephalopathic crises in early-diagnosed patients. Therefore, GCDH deficiency is now considered to be a treatable condition. However, significant differences exist in the diagnostic procedure and management of affected patients so that there is a wide variation of the outcome, in particular of pre-symptomatically diagnosed patients. At this time of rapid expansion of neonatal screening for GCDH deficiency, the major aim of this guideline is to re-assess the common practice and to formulate recommendations for diagnosis and management of GCDH deficiency based on the best available evidence.

Child↗
PubMed2004

Neonatal screening for glutaryl-CoA dehydrogenase deficiency.

Acute encephalopathic crisis in glutaryl-CoA dehydrogenase deficiency results in an unfavourable disease course and poor outcome, dominated by dystonia, feeding problems, seizures and secondary complications, and quite often leading to early death. The prerequisite for the prevention of irreversible brain damage in this disease is the detection of affected patients and initiation of treatment before the manifestation of such crisis. Apart from macrocephaly there are no signs or symptoms characteristic for this disease in presymptomatic children and, thus, they are usually missed. In some countries, implementation of extended neonatal screening programmes using electrospray ionization tandem mass spectrometry (ESI-MS/MS) allows detection of affected newborns and start of therapy before onset of neurological complications. This article summarizes recent strategies, pitfalls and shortcomings of a mass screening for glutaryl-CoA dehydrogenase deficiency using ESI-MS/MS. Furthermore, an alternative strategy, namely DNA-based neonatal screening for the Oji-Cree variant of this disease, is demonstrated. An optimization of diagnostic as well as therapeutic procedures must be achieved before GCDH deficiency unequivocally fulfills the criteria of a reliable and successful newborn screening programme.

Amino Acid Metabolism, Inborn Errors↗
PubMed2004

Maintenance treatment of glutaryl-CoA dehydrogenase deficiency.

This paper summarizes the published experience as well as results of the 3rd International Workshop on Glutaryl-CoA Dehydrogenase Deficiency held in October 2003 in Heidelberg, Germany, on the topic treatment of patients with glutaryl-CoA dehydrogenase (GCDH) deficiency. So far no international recommendation for treatment of GCDH deficiency exists. Such an approach is hampered by several facts, namely the lack of an in-depth understanding of the pathophysiology of the disease, the lack of prospective studies, including the evaluation of drug monotherapy, and lack of objective documentation of clinical changes (e.g. video documentation) during pharmacotherapy.

Amino Acid Metabolism, Inborn Errors↗
PubMed2004

Emergency treatment in glutaryl-CoA dehydrogenase deficiency.

The history of glutaryl-CoA dehydrogenase deficiency is determined by acute encephalopathic crises that are precipitated by common febrile diseases, vaccinations or surgical interventions during infancy and early childhood. Such crises result in an irreversible destruction of the basal ganglia (in particular of the putamina), and consequently dystonia, dyskinesia and choreoathetosis. Secondary complications include feeding and speech problems, failure to thrive, recurrent aspiration, immobilization, severe motor deficits and early death. It is generally accepted that maintenance treatment based on dietary lysine or protein restriction and supplementation with carnitine (and riboflavin) is insufficient to prevent acute crises during intercurrent illnesses or conditions that enhance catabolic state. Consequently, outpatient and inpatient emergency therapies have been implemented. The present review describes a recommended approach to emergency therapy for this disease.

Amino Acid Metabolism, Inborn Errors↗
PubMed2004

Looking forward--an evidence-based approach to glutaryl-CoA dehydrogenase deficiency.

Three decades after the first description of glutaryl-CoA dehydrogenase deficiency, major progress has been achieved in the prevention of acute striatal necrosis and neurological sequelae in affected children, if diagnosis is made early and treatment is started before manifestation of acute encephalopathic crises. However, all concepts for diagnostic work-up, monitoring, and treatment are solely experience-based, and 10-35% of early-diagnosed children do not or only incompletely benefit from the current management. They still develop neurological deterioration and sequelae despite early implementation of dietary treatment, carnitine supplementation and emergency treatment during acute intercurrent illnesses. International efforts should be made to move management of affected children from experience-based to evidence-based medicine. Major tools for this optimization are the establishment of an international patients' database, the implementation of an international prospective clinical study, and the development of international guidelines for diagnostic work-up, monitoring and therapy.

Amino Acid Metabolism, Inborn Errors↗
PubMed2003

Bowen-Conradi syndrome: a clinical and genetic study.

The purpose of the study was to delineate the anomalies and the natural life history of persons with the Bowen-Conradi syndrome [Bowen and Conradi 1976: Birth Defects: Orig Artic Ser XII(6):101-108]. We ascertained 39 cases and personally examined almost all. For those who were not seen, their clinical record were scrutinized. Pedigree analysis of all 39 was done and kinship coefficients computed. The birth prevalence was estimated to be 1/355 live births.

Craniofacial Abnormalities↗
PubMed2002

Outcome of the first 3-years of a DNA-based neonatal screening program for glutaric acidemia type 1 in Manitoba and northwestern Ontario, Canada.

Glutaric acidemia type 1 (GA1) is overrepresented in the aboriginal population of Island Lake, Manitoba, and northwestern Ontario who speak the Ojibway-Cree (Oji-Cree) dialect. The carrier frequency in these communities has been predicted to be as high as 1 in 10 individuals. Prior to beginning newborn screening for GA1 in May 1998, 18 of 20 affected patients diagnosed at this center have been from these high-risk communities. Most have followed an acute encephalopathic course with permanent neurologic sequelae and high mortality. They excrete small amounts of glutaric acid and 3-hydroxyglutaric acid and have significant residual enzyme activity. A single homozygous mutation in glutaryl-CoA-dehydrogenase (GCDH IVS-1 + 5g right arrow t) has been identified in this population. DNA-based newborn screening targeted to our high-risk communities was begun in order to provide presymptomatic detection and treatment of affected patients. Of the first 1176 newborns screened, 4 affected infants were identified and treated with a low-protein diet, carnitine, and riboflavin. All 4 infants have required numerous hospitalizations for treatment of intercurrent illnesses. Eventually, 3 infants presented with acute dystonic encephalopathy and seizures along with permanent neurological sequelae. One of these infants died unexpectedly at home at 18 months of age. The fourth, now 9 months old, has had a gastrostomy tube placed to facilitate fluid replacement in addition to a standard treatment protocol and is doing well. The reasons for our initial disappointing outcomes in the first 3 of 4 affected babies are likely multiple. Based on our early experience and that of other centers screening newborns for GA1, current therapeutic strategies may be insufficient in preventing the occurrence of neurologic sequelae in some children. An incomplete understanding of the neurotoxic mechanisms underlying this devastating disorder hampers effective management.

Canada↗
PubMed2002

Reproductive fitness in maternal homocystinuria due to cystathionine beta-synthase deficiency.

Early diagnosis and improved treatment are leading to the potential for increased reproductive capability in homocystinuria due to cystathionine beta-synthase (CbetaS) deficiency, but information about reproductive outcome and risk of thromboembolism in pregnancy is limited. To provide further information, clinical and biochemical information was obtained on women with maternal homocystinuria, on their pregnancies and on the offspring. This information included blood sulphur amino acids and total homocysteine, CbetaS gene mutations and developmental and cognitive scores in the offspring. The study involved 15 pregnancies in 11 women, of whom 5 were pyridoxine-nonresponsive and 6 were pyridoxine-responsive. Complications of pregnancy included pre-eclampsia at term in two pregnancies and superficial venous thrombosis of the leg in a third pregnancy. One pregnancy was terminated and two pregnancies resulted in first-trimester spontaneous abortions. The remaining 12 pregnancies produced live-born infants with normal or above-normal birth measurements. One offspring has multiple congenital anomalies that include colobomas of the iris and choroid, neural tube defect and undescended testes. He is also mentally retarded and autistic. A second offspring has Beckwith-Wiedemann syndrome. The remaining 10 offspring were normal at birth and have remained normal. There was no relationship between the severity of the biochemical abnormalities or the therapies during pregnancy to either the pregnancy complications or the offspring outcomes. The infrequent occurrences of pregnancy complications, offspring abnormalities and maternal thromboembolic events in this series suggest that pregnancy and outcome in maternal homocystinuria are usually normal. Nevertheless, a cautious approach would include careful monitoring of these pregnancies with attention to metabolic therapy and possibly anticoagulation.

Adolescent↗
PubMed2002

Cryptic chromosome rearrangements detected by subtelomere assay in patients with mental retardation and dysmorphic features.

The regions near telomeres of human chromosomes are gene rich. Chromosome subtelomere rearrangements occur with a frequency of 7-10% in children with mild-to-moderate mental retardation (MR) and approximately 50% of cases are familial. Clinical investigation of subtelomere rearrangements is now prompted by fluorescence in situ hybridization (FISH) analysis using specific DNA probes from all relevant chromosome ends. In our study, 40 children were selected for subtelomere assay using either the Chromophore Multiprobe-T Cytocell device or the VYSIS TelVision probes. Inclusion criteria were: developmental delay or MR; a normal 550 G-band karyotype; FRAXA negative; and at least one other clinical criterion. Exclusion criteria included an identified genetic or environmental diagnosis. Of the 40 patients analysed, four (10%) were found to have subtelomere rearrangements. Three of 40 (7.5%) were found to have an unbalanced subtelomere rearrangement and one of 40 (2.5%) was found to have an apparently normal variant subtelomere deletion. The first of the three with an unbalanced karyotype was the result of a familial translocation, the second was a de novo finding, and the origin of the third could not be determined. The subtelomere FISH assay detected almost twice the frequency of unbalanced karyotypes as those detected by 550 G-banding in our cytogenetics laboratory (4.7%). In addition, subtelomere screening was eight times more likely than fragile X screening in our DNA laboratory (1%) to detect genetic abnormalities in mentally handicapped individuals. Our findings support the view that screening for subtelomere rearrangements has a greater positive yield than other commonly used genetic investigations and, if cost and resources permit, should be the next diagnostic test of choice in a child with unexplained MR/dysmorphisms and a normal 550 G-band karyotype.

Abnormalities, Multiple↗
PubMed2001

Novel and recurrent mutations in lamin A/C in patients with Emery-Dreifuss muscular dystrophy.

Emery-Dreifuss muscular dystrophy (EDMD) is characterized by slowly progressive muscle wasting and weakness; early contractures of the elbows, Achilles tendons, and spine; and cardiomyopathy associated with cardiac conduction defects. Clinically indistinguishable X-linked and autosomal forms of EDMD have been described. Mutations in the STA gene, encoding the nuclear envelope protein emerin, are responsible for X-linked EDMD, while mutations in the LMNA gene encoding lamins A and C by alternative splicing have been found in patients with autosomal dominant, autosomal recessive, and sporadic forms of EDMD. We report mutations in LMNA found in four familial and seven sporadic cases of EDMD, including seven novel mutations. Nine missense mutations and two small in-frame deletions were detected distributed throughout the gene. Most mutations (7/11) were detected within the LMNA exons encoding the central rod domain common to both lamins A/C. All of these missense mutations alter residues in the lamin A/C proteins conserved throughout evolution, implying an essential structural and/or functional role of these residues. One severely affected patient possesed two mutations, one specific to lamin A that may modify the phenotype of this patient. Mutations in LMNA were frequently identified among patients with sporadic and familial forms of EDMD. Further studies are needed to identify the factors modifying disease phenotype among patients harboring mutations within lamin A/C and to determine the effect of various mutations on lamin A/C structure and function.

Adult↗
PubMed2001

Birt-Hogg-Dubé syndrome, a genodermatosis associated with spontaneous pneumothorax and kidney neoplasia, maps to chromosome 17p11.2.

Birt-Hogg-Dubé syndrome (BHD), an inherited autosomal genodermatosis characterized by benign tumors of the hair follicle, has been associated with renal neoplasia, lung cysts, and spontaneous pneumothorax. To identify the BHD locus, we recruited families with cutaneous lesions and associated phenotypic features of the BHD syndrome. We performed a genomewide scan in one large kindred with BHD and, by linkage analysis, localized the gene locus to the pericentromeric region of chromosome 17p, with a LOD score of 4.98 at D17S740 (recombination fraction 0). Two-point linkage analysis of eight additional families with BHD produced a maximum LOD score of 16.06 at D17S2196. Haplotype analysis identified critical recombinants and defined the minimal region of nonrecombination as being within a <4-cM distance between D17S1857 and D17S805. One additional family, which had histologically proved fibrofolliculomas, did not show evidence of linkage to chromosome 17p, suggesting genetic heterogeneity for BHD. The BHD locus lies within chromosomal band 17p11.2, a genomic region that, because of the presence of low-copy-number repeat elements, is unstable and that is associated with a number of diseases. Identification of the gene for BHD may reveal a new genetic locus responsible for renal neoplasia and for lung and hair-follicle developmental defects.

Abnormalities, Multiple↗
PubMed2001

Third case of cerebral, ocular, dental, auricular, skeletal anomalies (CODAS) syndrome, further delineating a new malformation syndrome: first report of an affected male and review of literature.

CODAS syndrome (MIM# 600373) is a rare multiple congenital anomalies syndrome. The disorder is highly distinctive with characteristic features consisting of developmental delay, cataracts, unusual enamel projections, overfolded and crumpled ears, epiphyseal dysplasia, and dysmorphic features (grooved nose, ptosis). To date, there have been two affected female children reported. The first was a Canadian girl of Mennonite descent, reported by our group, and the second was a girl from Brazil. The etiology and pattern of inheritance of CODAS is unknown. Herein we report a third affected child, a Canadian male infant of Mennonite ancestry. The child, now two years old, exhibits ptosis, cataracts, overfolded ears, grooved nasal tip, dental projections, developmental delay, and characteristic skeletal anomalies. The findings are characteristic for CODAS syndrome. All investigations including karyotype, metabolic screening, peroxisomal studies, and studies of cholesterol biosynthesis were normal. The underlying defect responsible for CODAS syndrome remains unknown. Many of the features suggest a possible underlying collagen gene defect. The fact that this child is the second child from the Manitoba Mennonite community, a genetic isolate, suggests the possibility of autosomal recessive inheritance. To date, there has not been a familial recurrence.

Abnormalities, Multiple↗
PubMed2001

Hepatic carnitine palmitoyl transferase 1 (CPT1 A) deficiency in North American Hutterites (Canadian and American): evidence for a founder effect and results of a pilot study on a DNA-based newborn screening program.

We describe six patients with hepatic carnitine palmitoyl transferase (CPT1 A) deficiency who are members of a large extended Hutterite kindred living in widely scattered communities in the United States and Canadian Prairies. Two patients have significant neurological impairment due to severe recurrent hypoglycemic crises. The remaining four patients with earlier detection and treatment have near normal outcomes. The Canadian and American Hutterite families share two common ancestors who married in 1812, about 60 years before the Hutterites arrived in North America and prior to their subdivision into the three groups (Schmiedeleut, Dariusleut, and the Lehrerleut). These patients share a common haplotype on chromosome 11q13 and are all homozygous for a common CPT1 A G710E mutation, suggesting a founder effect. The clustering of such a rare disorder of fatty acid oxidation prompted us to initiate a pilot DNA-based neonatal screening program to determine the carrier frequency of this mutation in Hutterite newborns with the participation and support of the community. To date our carrier frequency is 1/16, close to the predicted frequency based on diagnosed patients and number of births. We believe our newborn screening program for CPT1 A deficiency in the Hutterite community will serve as a prototype model for delivery of targeted genetic services to other similar unique genetic isolates.

Adolescent↗
PubMed2001

Molecular and enzymatic characterization of a unique carnitine palmitoyltransferase 1A mutation in the Hutterite community.

Hepatic carnitine palmitoyltransferase 1 (CPT1A) deficiency is a rare disorder of mitochondrial fatty acid oxidation inherited as an autosomal recessive trait. Symptomatology comprises attacks of hypoketotic hypoglycemia with risk of sudden death or neurological sequelae. Only one CPT1A mutation has been reported so far. Identification of the disease-causing mutations allows both insights into the structure-function relationships of CPT1A and management of the patients and their relatives. The molecular analysis of CPT1A deficiency in a large Hutterite kindred illustrates this point. Both cDNA and genomic DNA analysis demonstrate that the affected patients are homozygous for a 2129G>A mutation predicting a G710E substitution. Studies in fibroblasts from one patient as well as heterologous expression of the mutagenized CPT1A in yeast show that the G710E mutation alters neither mitochondrial targeting nor stability of the CPT1A protein. By contrast, kinetic studies conclusively establish that the mutant CPT1A is totally inactive, indicating that the G710E mutation dramatically impairs the catalytic function of CPT1A. Finally, due to a strongly suspected founder effect for the origin of CPT1A deficiency in this Hutterite kindred, identification of this disease-causing mutation allows the setup of a targeted DNA-based newborn screening in this at-risk population.

Amino Acid Sequence↗
PubMed2001

Protein-sensitive and fasting hypoglycemia in children with the hyperinsulinism/hyperammonemia syndrome.

OBJECTIVE: Because the hyperinsulinism/hyperammonemia (HI/HA) syndrome is associated with gain of function mutations in the leucine-stimulated insulin secretion pathway, we examined whether protein feeding or fasting was responsible for hypoglycemia in affected patients. STUDY DESIGN: Patients with HI/HA (8 children and 6 adults) were studied. All had dominantly expressed mutations of glutamate dehydrogenase and plasma concentrations of ammonium that were 2 to 5 times normal. The responses to a 24-hour fasting test were determined in 7 patients. Responses to a 1.5 gm/kg oral protein tolerance test in 12 patients were compared with responses of 5 control subjects. RESULTS: The median age at onset of hypoglycemia in the 14 patients was 9 months; diagnosis was delayed beyond age 2 years in 6 patients, and 4 were not given a diagnosis until adulthood. Fasting tests revealed unequivocal evidence of hyperinsulinism in only 1 of 7 patients. Three did not develop hypoglycemia until 12 to 24 hours of fasting; however, all 7 demonstrated inappropriate glycemic responses to glucagon that were characteristic of hyperinsulinism. In response to oral protein, all 12 patients with HI/HA showed a fall in blood glucose compared with none of 5 control subjects. Insulin responses to protein loading were similar in the patients with HI/HA and control subjects. CONCLUSION: The postprandial blood glucose response to a protein meal is more sensitive than prolonged fasting for detecting hypoglycemia in the HI/HA syndrome.

Adolescent↗
PubMed2001

A comprehensive analysis of MNG1, TCO1, fPTC, PTEN, TSHR, and TRKA in familial nonmedullary thyroid cancer: confirmation of linkage to TCO1.

About 5% of nonmedullary thyroid cancer is familial. These familial nonmedullary thyroid cancer cases are characterized by an earlier age of onset, more aggressive phenotype, and in some families a high propensity to benign thyroid disease. Little is known about the genes conferring predisposition to nonmedullary thyroid cancer. Three loci have been identified through genetic linkage: MNG1 on 14q32, TCO1 on 19p13.2, and fPTC on 1p21. In addition to these putative genes, a number of loci represent candidate familial nonmedullary thyroid cancer predisposition genes by virtue of their involvement in sporadic disease (TRKA), their role in benign disease (TSHR), and because they underlie syndromes with a risk of nonmedullary thyroid cancer (PTEN). To evaluate the roles of MNG1, TCO1, fPTC, PTEN, TSHR, and TRKA in familial nonmedullary thyroid cancer, we have carried out a comprehensive mutation and linkage analysis of these genes in 22 families. One family was linked to chromosome 19q13.2, confirming that TCO1 underlies a subset of familial nonmedullary thyroid cancer. None of the families was linked to MNG1 or fPTC, and there was no evidence to support the roles of PTEN, TSHR, or TRKA. Familial nonmedullary thyroid cancer is an emerging clinical phenotype that is genetically heterogeneous, and none of the currently identified genes accounts for the majority of families.

Adult↗
PubMed2000

Identical dysferlin mutation in limb-girdle muscular dystrophy type 2B and distal myopathy.

Limb-girdle muscular dystrophy type 2B (LGMD2B) and Miyoshi myopathy (MM) are autosomal recessive disorders caused by mutations in the dysferlin gene on chromosome 2p13. The authors studied a large Russian family with both LGMD2B and MM. All affected individuals, as well as one preclinical boy with dystrophic changes on muscle biopsy, were found to be homozygous for a novel dysferlin mutation, TG573/574AT (Val67Asp). This finding supports the view that additional factors (e.g., modifier genes) contribute to the phenotypic expression of causative mutations in dysferlinopathies.

Adult↗