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Biomedical subjects

S Packman

Publications and source records attributed to S Packman.

At least 19 recordsLinked to original sources

Psychological complications of patients with Gaucher disease.

The Minnesota Multiphasic Personality Inventory (MMPI-2) is commonly used in chronic illness and chronic pain populations to assess psychological functioning. We report the results of the first study employing the MMPI-2 to assess psychological aspects of patients with Gaucher disease, type I (GD) is an inborn error of metabolism with unique features as a chronic illness: the disorder often presents with mild symptoms, and is frequently diagnosed in later childhood or adulthood; the treatment is highly efficacious, but, that same treatment is intrusive and expensive and requires that patients restructure their work and personal schedules. In this study, 28 patients with GD completed the MMPI-2 and a background questionnaire. GD patients scored significantly higher than the MMPI-2 normative sample on MMPI-2 scales of Validity (K), Hypochondriasis (Hs), Depression (D), Hysteria (Hy), Psychasthenia (Pt) and Schizophrenia (Sc). Individuals with elevated scores on the Hs, D and Hy scales tend to have somatic concerns and depressed mood. Under stress, they are likely to report physical symptoms. Elevated Pt and Sc scales suggest psychological turmoil and, possibly feelings of isolation. An elevated K scale indicates a tendency for individuals to deny psychopathology. The length of time the patient with GD had been on enzyme replacement therapy was not significantly related to any of the 13 MMPI-2 scales. Cohorts of patients with chronic heart disease (CRHD) and cohorts of patients with chronic pain were utilized as comparative populations in this investigation. The elevated scores of the GD patients on MMPI-2 scales Hs, D and Hy were similar to those of the CRHD population. The chronic pain patients also showed elevations on MMPI-2 scales Hs, D and Hy, which were elevated in the GD patients; the elevations in the chronic pain patients were higher than those shown by the GD patients. We conclude that patients with GD exhibit moderate to severe psychological complications, similar to patients with other long-term chronic illnesses.

Adolescent↗

Galactosaemia: early treatment with an elemental formula.

Classical galactosaemia is caused by deficient galactose-1-phosphate uridyl transferase activity, and is treated by dietary galactose restriction. Despite dietary treatment, long-term outcomes have not been uniformly favourable. Late complications may include speech abnormalities, ataxia, cognitive impairment, growth delay, bone alterations and ovarian failure. We report an infant whose erythrocyte galactose 1-phosphate (gal-1-P) levels remained well above the treatment range on a low-galactose (soy) formula. Once she was begun on an elemental formula (galactose-free), gal-1-P levels decreased rapidly to within the treatment range. Urine galactitol levels decreased on the elemental formula but were within published treatment ranges despite treatment changes. These did not correlate with the gal-1-P levels. This case suggests further study be considered to determine whether a truly galactose-free diet in infancy could alter the long-term prognosis of classical galactosaemia.

Erythrocytes↗

Relationship of primary mitochondrial respiratory chain dysfunction to fiber type abnormalities in skeletal muscle.

Variation in the size and relative proportion of type 1 and type 2 muscle fibers can occur in a number of conditions, including structural myopathies, neuropathies, and various syndromes. In most cases, the pathogenesis of such fiber type changes is unknown and the etiology is heterogeneous. Skeletal muscle mitochondrial respiratory chain analysis was performed in 10 children aged 3 weeks to 5 years with abnormalities in muscle fiber type, size, and proportion. Five children were classified as having definite, four as probable, and one as possible mitochondrial disease. Type 1 fiber predominance was the most common histological finding (six of 10). On light microscopy, four cases had subtle concomitants of a mitochondriopathy, including mildly increased glycogen, lipid, and/or succinate dehydrogenase staining, and one case had more prominent evidence of underlying mitochondrial disease with marked subsarcolemmal staining. Most cases (nine of 10) had abnormal mitochondrial morphology on electron microscopy. All were found to have mitochondrial electron transport chain (ETC) abnormalities and met diagnostic criteria for mitochondrial disease. We did not ascertain any patients who had isolated fiber type abnormalities and normal respiratory chain analysis during the period of study. We conclude that mitochondrial ETC disorders may represent an etiology of at least a subset of muscle fiber type abnormalities. To establish an etiologic diagnosis and to determine the frequency of such changes in mitochondrial disease, we suggest analysis of ETC function in individuals with fiber type changes in skeletal muscle, even in the absence of light histological features suggestive of mitochondrial disorders.

Child, Preschool↗

Periventricular heterotopia associated with chromosome 5p anomalies.

Periventricular heterotopia (PH) is characterized by neuronal nodules along the lateral ventricles. Whereas mutations in X-linked FLNA cause such cortical malformations, the authors report two cases of PH localizing to chromosome 5p. Both subjects have complex partial seizures. MRI demonstrated bilateral nodular PH, with subcortical heterotopia or focal gliosis. FISH identified a duplication of 5p15.1 [46,XX,dup(5)(p15.1p15.1)] and a trisomy of 5p15.33 [46,XY,der(14)t(5;14)(p15.33;p11.2) mat]. These findings suggest a new PH locus along the telomeric end of chromosome 5p.

Abnormalities, Multiple↗

Mutation analysis of copper transporter genes in patients with ethylmalonic encephalopathy, mitochondriopathies and copper deficiency phenotypes.

The trace metal copper is an essential cofactor for a number of biological processes, including mitochondrial oxidative phosphorylation, free-radical eradication, neurotransmitter synthesis and maturation, and iron metabolism. Consequently, copper transport at the cell surface and the delivery of copper to intracellular proteins are critical events in normal cellular homeostasis. Four genes have been reported to influence the cellular uptake and the delivery of copper to specific cell compartments and proteins. These include hCTR1, which regulates cellular copper uptake; HAH1, which mediates the transfer of copper to the Menkes and Wilson disease transporters; CCS, which is related to the transfer of copper to superoxide dismutase; and hCOX17, which directs trafficking of copper to mitochondrial cytochrome-c oxidase. At present, no genetic disorders have been associated with defects in these four copper transporter genes. In this study, we test the possibility that defective copper uptake or intracellular translocation represents the basic defect in three categories of candidate phenotypes among 22 patients: ethylmalonic encephalopathy; mitochondriopathies of unknown aetiology; and neurodevelopmental abnormalities with clinical and chemical evidence of copper deficiency. Mutation analyses of the copper uptake protein, hCTR1, and the three copper chaperones were performed by direct sequencing of the whole coding regions. No causative mutations were identified for the four copper transporter genes in 22 patients. A heterozygous polymorphism (847G>A) for CCS was detected in 7 patients. For the distinct disease entity ethylmalonic encephalopathy, we additionally show normal mRNA levels for each of the four genes. The negative results notwithstanding, we encourage ongoing study of additional patients with candidate phenotypes. Further, our results are consistent with the notion that other unknown copper-related transporters could be involved in diseases.

Blotting, Northern↗

Hyperammonemia in urea cycle disorders: role of the nephrologist.

Hyperammonemia associated with inherited disorders of amino acid and organic acid metabolism is usually manifested by irritability, somnolence, vomiting, seizures, and coma. Although the majority of these patients present in the newborn period, they may also present in childhood, adolescence, and adulthood with failure to thrive, persistent vomiting, developmental delay, or behavioral changes. Persistent hyperammonemia, if not treated rapidly, may cause irreversible neuronal damage. After the diagnosis of hyperammonemia is established in an acutely ill patient, certain diagnostic tests should be performed to differentiate between urea cycle defects and other causes of hyperammonemic encephalopathy. In a patient with a presumed inherited metabolic disorder, the aim of therapy should be to normalize blood ammonia levels. Recent experience has provided treatment guidelines that include minimizing endogenous ammonia production and protein catabolism, restricting nitrogen intake, administering substrates of the urea cycle, administering compounds that facilitate the removal of ammonia through alternative pathways, and, in severe cases, dialysis therapy. Initiation of dialysis in the encephalopathic patient with hyperammonemia is indicated if the ammonia blood level is greater than three to four times the upper limit of normal. Hemodialysis is the most effective treatment for rapidly reducing blood ammonia levels. Continuous hemofiltration and peritoneal dialysis are also effective modalities for reducing blood ammonia levels. An improved understanding of the metabolism of ammonia and neurological consequences of hyperammonemia will assist the nephrologist in providing optimal care for this high-risk patient population.

Algorithms↗

Clinical course and biochemistry of sialuria.

Sialuria is a rare inborn error of metabolism in which excessive free sialic acid (N-acetylneuraminic acid, NeuAc) is synthesized. A defect in the feedback inhibition of UDP-N-acetylglucosamine (UDP-GlcNAc) 2-epimerase by the end-product of the sialic acid synthetic pathway, CMP-NeuAc, is the mechanism underlying this overproduction. Recent evidence suggests that sialuria is an autosomal dominant disorder. Only five patients have been documented to have such an enzymatic defect. We report a longitudinal study of one of the original sialuria patients, to age 11 years. Although he has coarse features and massive hepatomegaly, he has shown normal growth and relatively normal development. Pulmonary function testing showed minimal small airway obstruction. At 11 years, he developed intermittent abdominal pain and transient transaminase elevation above his baseline. Sialuria should be considered in the differential diagnosis of a patient with a phenotype suggestive of a mucopolysaccharidosis or oligosaccharidosis in the absence of developmental regression or prominent dysostosis multiplex. We recommend close monitoring of liver and pulmonary function in sialuria patients.

Abdominal Pain↗

A case of PDH-E1 alpha mosaicism in a male patient with severe metabolic lactic acidosis.

We have characterized a novel mutation in a male patient that affects the coding sequence of PDH-E1 alpha gene and changes arginine-141 to a leucine. This nucleotide substitution was found in about 75% of the studied DNA (fibroblasts, liver and muscle), a scenario that would indicate a case of E1 alpha mosaicism in a male patient. When the mutant E1 alpha protein was expressed in human skin fibroblasts with zero endogenous pyruvate dehydrogenase complex activity and E1 alpha protein expression, no significant restoration of activity was recorded, in contrast to the wild-type cDNA. even though both wild-type and mutant protein levels were comparable. We concluded that the R141L mutation is a severe one and that it must have occurred in one of the E1 alpha alleles during early embryogenesis.

Acidosis, Lactic↗

The molecular basis of human 3-methylcrotonyl-CoA carboxylase deficiency.

Isolated biotin-resistant 3-methylcrotonyl-CoA carboxylase (MCC) deficiency is an autosomal recessive disorder of leucine catabolism that appears to be the most frequent organic aciduria detected in tandem mass spectrometry-based neonatal screening programs. The phenotype is variable, ranging from neonatal onset with severe neurological involvement to asymptomatic adults. MCC is a heteromeric mitochondrial enzyme composed of biotin-containing alpha subunits and smaller beta subunits. Here, we report cloning of MCCA and MCCB cDNAs and the organization of their structural genes. We show that a series of 14 MCC-deficient probands defines two complementation groups, CG1 and 2, resulting from mutations in MCCB and MCCA, respectively. We identify five MCCA and nine MCCB mutant alleles and show that missense mutations in each result in loss of function.

Alleles↗

Mitochondrial respiratory chain complex I deficiency with clinical and biochemical features of long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency.

The mitochondrial respiratory chain and the fatty acid oxidation cycle are theoretically interdependent on each other for normal function. We describe a patient with complex I deficiency who had clinical and biochemical features of long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency including liver failure, cardiomyopathy, and consistent urine organic acid pattern. Patients with features of either a respiratory chain or fatty acid oxidation disorder should have the defect characterized biochemically because of the implications with respect to potential therapy and genetic counseling.

3-Hydroxyacyl CoA Dehydrogenases↗

Progressive neurological deterioration and MRI changes in cblC methylmalonic acidaemia treated with hydroxocobalamin.

Cobalamin C (cblC) defects result in decreased activity of both methylmalonyl-CoA mutase and N5-methyltetrahydrofolate:homocysteine methyltransferase (methionine synthase), with subsequent methylmalonic acid-uria and homocystinuria. Patients typically show failure to thrive, developmental delay and megaloblastic anaemia. Vitamin B12 therapy has been beneficial in some cases. We report a now 4-year-old Hispanic girl with cblC disease documented by complementation analysis, with progressive neurological deterioration and worsening head MRI changes while on intramuscular hydroxocobalamin begun at age 3 weeks. Oral carnitine and folic acid were added at age 1 year. Blood levels of methylmalonic acid were reduced to treatment ranges. In the absence of acute metabolic crises, she developed microcephaly, progressive hypotonia and decreased interactiveness. Funduscopic examination was normal at age 13 months. At age 19 months, she developed nystagmus, and darkly pigmented fundi and sclerotic retinal vessels were observed on examination. Her neonatal head MRI was normal. By age 1 year, the MRI showed diffuse white-matter loss with secondary third and lateral ventricle enlargement, a thin corpus callosum, and normal basal ganglia. At age 15 months, progression of the white-matter loss, as well as hyperintense globi pallidi, were present. Interval progression of both grey- and white-matter loss was seen at age 27 months. We therefore caution that progressive neurological deterioration and head MRI abnormalities may still occur in cblC disease, despite early initiation of hydroxocobalamin therapy and improvement in toxic metabolite concentrations in physiological fluids.

Brain↗

Molecular correlations in phenylketonuria: mutation patterns and corresponding biochemical and clinical phenotypes in a heterogeneous California population.

We studied 133 California phenylketonuria (PKU) patients and one obligate heterozygote to delineate the molecular basis of PKU in a population with greater ethnic diversity than in previous studies, and to determine whether a correlation exists between genotype and clinical phenotype, with the latter defined by both the diagnostic pretreatment blood phenylalanine (PHE) level and cognitive (IQ) test scores. To determine PAH genotypes, we used PCR-mediated amplification, denaturing gradient gel electrophoresis, and direct sequencing on dried whole blood samples. Where possible, mutation severity was defined according to predicted in vitro PAH enzyme activity estimated by using Cos cell expression analysis for a given mutation. We then asked whether mutation severity, as defined by such expression analysis, correlated with pretreatment PHE levels or with IQ test results. A mutation was identified in 236 (88%) of 267 mutant alleles. Seventeen new mutant alleles were found; A47E, T81P, I102T, E182G, T328D, Y343P, K371R, Y387H, A389E, E422K, IVS9nt5, IVS11nt20, delS70, del364-368/del198-220, delF299, delT323, and -1C/T. In striking contrast to a number of studies in other populations, in this study, based on predicted PAH activity, we observed no correlation between mutation severity and pretreatment PHE levels. There was also no correlation between genotype and IQ. We conclude that in samples collected from an ethnically heterogeneous population, there is no correlation of mutation severity with either pretreatment PHE levels or IQ measurement in treated patients. We caution that genetic counseling in PKU should incorporate the notion that prognosis may not be predicted with precision based on mutation analysis in a given patient.

California↗

The molecular basis of medium-chain acyl-CoA dehydrogenase (MCAD) deficiency in compound heterozygous patients: is there correlation between genotype and phenotype?

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is the most commonly recognized defect of mitochondrial beta-oxidation. It is potentially fatal, but shows a wide clinical spectrum. The aim of the present study was to investigate whether any correlation exists between MCAD genotype and disease phenotype. We determined the prevalence of the 14 known and seven previously unknown non-G985 mutations in 52 families with MCAD deficiency not caused by homozygosity for the prevalent G985 mutation. This showed that none of the non-G985 mutations are prevalent, and led to the identification of both disease-causing mutations in 14 families in whom both mutations had not previously been reported. We then evaluated the severity of the mutations identified in these 14 families. Using expression of mutant MCAD in Escherichia coli with or without co-overexpression of the molecular chaperonins GroESL we showed that five of the missense mutations affect the folding and/or stability of the protein, and that the residual enzyme activity of some of them could be modulated to a different extent depending on the amounts of available chaperonins. Thus, some of the missense mutations may result in relatively high levels of residual enzyme activity, whereas the mutations leading to premature stop codons will result in no residual enzyme activity. By correlating the observed types of mutations identified to the clinical/biochemical data in the 14 patients in whom we identified both disease-causing mutations, we show that a genotype/phenotype correlation in MCAD deficiency is not straightforward. Different mutations may contribute with different susceptibilities for disease precipitation, when the patient is subjected to metabolic stress, but other genetic and environmental factors may play an equally important role.

Acyl-CoA Dehydrogenase↗

Developmental expression of the mouse mottled and toxic milk genes suggests distinct functions for the Menkes and Wilson disease copper transporters.

Menkes disease and Wilson disease are human disorders of copper transport caused by mutations in distinct genes encoding similar copper-transporting P-type ATPases. These genes are expressed in different adult tissues in patterns reflecting disease manifestations. The mouse homologues for the Menkes (MNK) and Wilson (WND) disease genes are the mottled (Atp7a) and toxic milk (Atp7b) genes, respectively. Using RNA in situ hybridization we describe the distribution of mottled and toxic milk transcripts during mouse embryonic development. The mottled gene is expressed in all tissues throughout embryogenesis and is particularly strong in the choroid plexuses of the brain. Mottled expression in the liver is in contrast to the prior observation of absent or very low expression in the adult liver. Expression of the toxic milk gene is significantly more delimited, with early expression in the central nervous system, heart and liver. Later in gestation, toxic milk transcript is clearly seen in the liver, intestine, thymus and respiratory epithelium including nasopharynx, trachea and bronchi. In lung, toxic milk expression is restricted to bronchi, while mottled expression is diffuse. Hepatic expression of both toxic milk and mottled is in the parenchyma, as opposed to blood cells. These results suggest that the mottled gene product functions primarily in the homeostatic maintenance of cell copper levels, while the toxic milk gene product may be specifically involved in the biosynthesis of distinct cuproproteins in different tissues.

Adenosine Triphosphatases↗

Mutation analysis and expression of the mottled gene in the macular mouse model of Menkes disease.

The gene for Menkes disease, an X-linked disorder of copper transport, has recently been identified and shown to encode a copper-transporting P-type ATPase. The macular mutant mouse has been proposed as an animal model for Menkes disease. In the present study, we report the finding of a missense mutation in the mottled gene of the macular mouse. A single base change, T to C, at nucleotide position 4223, is predicted to result in an amino acid change from serine to proline at residue 1382 in the eighth transmembrane domain. This mutation differs from the 6-bp deletion we find in brindled cDNA. With validation of macular as an animal model of Menkes disease, we compared mottled gene expression in the intestine, kidney, and brain of macular and normal mice. In Northern analyses an 8.3-kb transcript was detected in the intestine, kidney, and brain of both normal and macular mice, with the level of transcript in macular approximately 80% that of normal. In situ hybridization studies revealed that the mottled gene was clearly expressed in intestinal epithelial cells, Paneth cells, and renal proximal tubular cells of both normal and macular mice. In normal brain, mottled gene expression was most intensely observed in the choroid plexus, in Ammon's born and the dentate gyrus in the hippocampus, in Purkinje cells, and the granular layer of the cerebellum. The intensity and localization of the signals in the brain of macular mice were similar to those of the controls. The distribution of expression of mottled is correlated with cells and tissues showing histopathology or abnormal copper sequestration in macular and other mutants.

Adenosine Triphosphatases↗

Methylmalonic acidemia, cobalamin C type, presenting with cutaneous manifestations.

BACKGROUND: Erosive dermatitis resembling the skin lesions of acrodermatitis enteropathica has been described in a number of aminoacidopathies and organic acidemias. In some, the dermatitis is a manifestation of untreated disease, while in others, including methylmalonic acidemia, skin lesions have been ascribed to nutritional deficiency due to therapeutic amino acid restrictions. OBSERVATIONS: We report 2 cases of methylmalonic acidemia presenting with cutaneous manifestations in the perinatal period before restrictive nutritional interventions. The cutaneous involvement consisted of cheilitis and diffuse erythema with erosions and desquamation. Methylmalonic acidemia, cobalamin C type, was subsequently diagnosed in both cases. CONCLUSIONS: An erosive, desquamating dermatitis with histopathologic characteristics resembling acrodermatitis enteropathica may be a presenting sign in cobalamin C methylmalonic acidemia, even in the absence of long-standing nutritional restrictions or deficiency.

Acrodermatitis↗