Search PubMed⌕ Search

Biomedical subjects

G G Gascon

Publications and source records attributed to G G Gascon.

At least 37 records · Page 2Linked to original sources
PubMed1994

Movement disorders in childhood organic acidurias. Clinical, neuroimaging, and biochemical correlations.

Over the last 5 years the Pediatric Neurology service at King Faisal Specialist Hospital and Research Centre (KFSH&RC) has seen 131 infants and children with movement disorders. Forty-nine (37%) had identifiable biochemical defects, 25 of which were organic acidemias. Nineteen of 29 patients with dystonia had organic acidemias, primarily glutaric aciduria type 1 (7 patients), bilateral striatal necrosis (4 patients), and 3-methyl glutaconic aciduria (3 patients). All patients with parkinsonian rigidity (n = 11) had organic acidemias; again, the greatest number accounted for by glutaric aciduria type 1 (7 patients), who had both parkinsonian rigidity combined with dystonia. Myoclonus occurred in only 1 of 25 and chorea in 7 of 25 patients with organic acidemias. At the least all patients had bilateral lesions of putamen and head of caudate, seen best in MRI brain scans as increased T2 signal intensities with normal volume, and later with volume loss.

Acidosis↗
PubMed1994

Neurophysiologic correlates of organic acidemias: a survey of 107 patients.

The files of 107 patients with 19 different types of organic acidemia were reviewed retrospectively. Approximately 50% of the patients had abnormal electroencephalogram (EEG) at the time of initial study. In patients who had serial studies, the EEG deteriorated in 38% and improved in 15%. The predominant EEG abnormality encountered was slowing of the background activity in various degrees. Focal or generalized paroxysmal activity occurring in conjunction with slow background activity indicated a poor prognosis. Brainstem auditory evoked potentials (BAEP), visual evoked potentials (VEP), and somatosensory evoked potentials (SEP) were analyzed. The VEP was abnormal in 44%, BAEP in 39%, and SEP in 29% of the patients. Given the magnitude and frequency by which neurophysiological abnormalities occur in organic acidemias, neurophysiology testing provides complementary functional information and has an important place in the clinical work-up of these diseases.

Acidosis↗
PubMed1994

Ataxia-ocular motor apraxia syndrome: an investigation of cellular radiosensitivity of patients and their families.

Although ataxia-ocular motor apraxia (AOA) has been described as a disease entity mimicking ataxia telangiectasia (AT), no radiobiological studies have been carried out on cells from patients with AOA to find their possible relationship to AT. In the present study, cultured fibroblasts from three patients with AOA and their asymptomatic relatives (parents and sibs) were, therefore, compared with those from a classical AT homozygote, an AT heterozygote, and four healthy subjects for cell survival after acute and chronic irradiation. While a moderately increased cellular sensitivity (compared to normal) was observed in two AOA patients and most of their relatives, the degree of their radiosensitivity was quite different from that of the AT homozygote after both acute and chronic irradiation. One AOA patient exhibited increased cellular sensitivity similar to that of a classical AT homozygote up to 4% survival level after chronic irradiation but not after acute irradiation. A comparison of peripheral blood lymphocytes from two AOA patients, an AT homozygote, and two normal controls for spontaneous and (acute) radiation induced chromosomal breaks also failed to show any similarity between AOA and AT. These data support the notion that AOA is different from classical AT, and may represent a distinct disease entity controlled by specific gene(s), or compound heterozygotes involving different AT genes promoting the manifestation of AOA characteristics.

Adolescent↗
PubMed1994

Sanfilippo type D presenting with acquired language disorder but without features of mucopolysaccharidosis.

A 7-year-old girl presented with a language disorder reminiscent of verbal auditory agnosia. Later, she proved to have defective N-acetylglucosamine-6-sulfate sulfatase, the enzyme deficient in Sanfilippo D syndrome. She did not show clinical features of mucopolysaccharidosis. The language disorder had a fluctuating course, which eventually evolved into a progressive dementing encephalopathy.

Agnosia↗
PubMed1993

A preliminary study of the relationship between central auditory processing disorder and attention deficit disorder.

Fifteen boys aged six to ten who met the criteria for attention deficit disorder (ADD) were compared with ten boys who did not have ADD in a double-blind, placebo-controlled, single-crossover study of methylphenidate. To assess the degree of overlap between ADD and central auditory processing disorder (CAPD), all subjects were assessed on parent and teacher behavior rating scales, as well as a battery of CAPD tests at baseline and after three and six weeks of treatment. Twelve of the 15 subjects with ADD and none of the subjects without ADD met the criteria for CAPD. The subjects with ADD also responded to stimulant treatment on the measures of both ADD and CAPD. The overlap in the symptomatology of these disorders, the finding that the criteria for both disorders were met in 12 of 15 cases and the sensitivity of both ADD and CAPD measures to treatment with methylphenidate suggest that ADD and CAPD are closely related disorders. The implications of these results are three-fold. First, sustained attention is a critical feature of performance on CAPD tests and the current diagnostic criteria for CAPD make a clinical separation of the two disorders problematic. Second, stimulants appear to be a useful treatment for the symptoms of both ADD and CAPD. Third, CAPD tests may be a useful measure of ADD symptomatology and response to stimulants.

Analysis of Variance↗
PubMed1992

Neurometabolic diseases at a national referral center: five years experience at the King Faisal Specialist Hospital and Research Centre.

Of 910 children under the age of 12 years referred to the national center, we were able to assign an etiology to 473 (52%). This group consisted of lysosomal storage diseases (32%), amino acid disorders (14%), organic acid disorders (16%), various chromosome abnormalities and syndromes with dysmorphia or brain dysgenesis (26%), and various other metabolic diseases (12%). While such amino acidemias as branched-chain amino acidemia (MSUD) in classic and intermediate forms (44%) and hyperphenylalaninemia (PKU) due to 6-pyruvoyltetrahydropterin synthase deficiency (6PTSD) (19%) were common, classic PKU was rare (16%). Methylmalonic acidemia (31%), 3-hydroxy-3-methylglutaryl-coenzyme A lyase deficiency (16%), and propionic acidemia (12%) were encountered more frequently than other types of organic acidemias. When compared to the number of referred Down's syndrome patients, the results suggested the birth of at least one infant with neurometabolic disease per 50 births. Five tribes of Saudi Arabia constituted 26% of the diagnosable neurometabolic diseases. Diseases such as MSUD, 6 PTSD, Sanfilippo syndrome type B, methylmalonic acidemia, homocystinuria, GM2 gangliosidosis Sandhoff variant, infantile central nervous system spongy degeneration (Canavan disease), and neuraminidase deficiency showed definite tribal occurrence. In addition, 32% to 42% of the definitely diagnosed, and 25% to 87% of patients with probable neurometabolic disease but without a definable etiology, had more than one sibling affected. It is concluded that the many rare autosomal diseases of Saudi Arabia are due to "founder effect" created by marriages occurring within tribal and extended family boundaries.

Brain Diseases, Metabolic↗
PubMed1992

Saudi variant of multiple sulfatase deficiency.

We describe eight patients with multiple sulfatase deficiency (MSD, or Austin's disease) who differ phenotypically from classic neonatal-, childhood-, or juvenile-onset MSD. The age of onset was in childhood. The patients presented with somatic and facial features of mucopolysaccharidosis reminiscent of Maroteaux-Lamy and Morquio syndromes. They differed from classic MSD by the presence of corneal cloudiness, macrocephaly, severe dysostosis multiplex, and gibbus and the absence of ichthyosis, retinal degeneration, severe deafness, severe mental retardation, and dementia. The main neurologic presentation was cervical cord compression due to axis abnormalities. Despite neuroradiologic evidence of white-matter changes, neurologic presentation was not like metachromatic leukodystrophy. The sulfatase deficiencies were more marked than in the classic juvenile form of MSD, but less marked than in the classic childhood-onset form of MSD. Steroid sulfatase activity was spared except in one patient. This Saudi variant of MSD accounts for 5% of all lysosomal storage diseases in the Cell Repository Registry of our Inborn Errors of Metabolism Laboratory.

Child↗
PubMed1992

Biochemical heterogeneity of infantile central nervous system spongy degeneration.

Aspartoacylase, the enzyme whose activity is deficient in infantile central nervous system spongy degeneration (Canavan-Van Bogaert-Bertrand disease), is detected as an approximately 59-kD protein in the Sephadex G-200 filtration of normal fibroblast extracts. The enzyme activity in homogenates of fibroblasts is protected by leupeptin, a protease inhibitor. In the absence of leupeptin, 90% of aspartoacylase activity is lost. In some patients with infantile spongy degeneration, no activity (less than 2%) can be detected. In some other patients with residual activity in fibroblasts, two separate peaks of enzyme are eluted with molecular weight corresponding to approximately 59 and 19 kD. Aspartoacylase activity in this latter group is protected to the same extent by the presence of leupeptin. However, the elution of two peaks is independent of the presence of leupeptin. This study indicates biochemical heterogeneity in the pathogenesis of infantile spongy degeneration.

Amidohydrolases↗
PubMed1992

Heterogeneity of carboxypeptidase activity in infantile-onset galactosialidosis.

The clinical presentation and laboratory findings in seven patients with neonatal/infantile-onset galactosialidosis are presented. We detected no carboxypeptidase activity in two of these patients, while an enzyme with different apparent Km, or both Km and Vm, were found in five others. We could not establish a correlation between the biochemical characteristics of carboxypeptidase and the age of onset, progression, or other clinical features of galactosialidosis.

Brain Diseases, Metabolic↗
PubMed1992

GM1 gangliosidosis type 2 in two siblings.

A sister and brother, now aged 7 and 9 years, presented with developmental arrest, gait disturbance, dementia, and a progressive myoclonic epilepsy syndrome with hyperacusis in the second year of life. Then, spastic quadriparesis led to a decerebrate state. In the absence of macular or retinal degeneration, organomegaly, and somatic-facial features suggesting mucopolysaccharidosis, the presence of hyperacusis together with sea-blue histiocytes in bone marrow biopsies and deficient beta-galactosidase activity but normal glucosidase, hexosaminidase, and neuraminidase activity on lysosomal enzyme assays constitutes the clinical-pathologic-biochemical profile of GM1 gangliosidosis type 2. This is a rare, late infantile onset, progressive gray-matter disease in which beta-galactosidase deficiency is largely localized to the brain, though it can be demonstrated in leukocytes and cultured skin fibroblasts. It must be distinguished from the Jansky-Bielschowsky presentation of neuronal ceroid lipofuscinosis, mitochondrial encephalopathy, lactic acidosis, strokelike episodes (MELAS) and myoclonic epilepsy with ragged-red fibers (MERRF) syndromes, atypical presentations of GM2 gangliosidoses (Tay-Sachs and Sandhoff's diseases), primary sialidosis (neuraminidase deficiency), galactosialidosis, and Alpers' disease.

Biopsy↗
PubMed1992

Congenital muscular dystrophy with abnormal radiographic myelin pattern.

We report 11 children with a homogeneous clinical syndrome affecting both sexes, characterized by weakness at birth, slowly improving course, weakness of all muscle groups, arreflexia, elevated blood creatine kinase, normal nerve conduction velocity, dystrophic changes on muscle biopsy, and diffuse periventricular cortical white-matter abnormalities with sparing of corpus callosum, internal capsule, and brain stem. We compare them to 48 other previously reported similar cases and designate them as altered myelin radiographic pattern congenital muscular dystrophy (CMD), which is the same as occidental CMD. We compare them to the other presently accepted phenotypes: progressive Fukuyama CMD, Walker-Warburg or cerebral-ocular CMD, and Santavuori or muscle-eye-brain CMD. We suggest that the different phenotypes are alleles of the same gene, which regulates or expresses a structural protein required for muscle integrity, myelination, and formation of the cortex. Such phenotypic diversity has been established for mutations of Xp21 in X-linked muscular dystrophies.

Biopsy↗
PubMed1992

Coincident neuraminidase and aspartoacylase deficiency associated with chromosome 9Q paracentric inversion in a Saudi family.

A large, consanguineous Saudi family with three members with sialidosis type 1 and five members with infantile central nervous system spongy degeneration of the brain (ICNSSD, or Canavan-Bertrand-van Bogaert disease) is described. The patients with sialidosis had normal aspartoacylase activity, while neuraminidase activity in the patients with ICNSSD was reduced. All patients had normal carboxypeptidase activity in their fibroblasts. In an additional member there was photic-induced epilepsy, but he had normal enzymes. Two of the patients and one normal brother, but not the parents, had pericentric inversion of chromosome 9q. We postulate that an unidentified gene function is responsible for varied expression of these neurodegenerative diseases in this family.

Amidohydrolases↗
PubMed1992

Riyadh chromosome breakage syndrome: mental retardation with depigmentation of the skin and hair.

A 20-month-old infant with "silvery-blond" hair color, widespread confettilike depigmentation of the skin, and mental retardation was found to have, in lymphocytes and fibroblast cultures, increased spontaneous chromosome breaks and breaks induced by both mitomycin and gamma-irradiation. The sister chromatid exchange frequency was normal. This child probably represents a new chromosome breakage syndrome.

Albinism↗
PubMed1992

Treatment of inherited neurometabolic diseases: the future.

The past 10 years' experience with bone marrow transplantation from normal, immunologically compatible donors indicates its possible use in various neurometabolic diseases, particularly in a patient who has not suffered irreparable brain damage. This experience may be a prelude to treatment by somatic gene therapy. This can be applied as an autologous bone marrow transplant, grafting the patient's own stem cells inserted with the normal gene. Although somatic gene therapy will be relatively easy for tissues with dividing cells, its application to target tissues with little or no cell division may pose difficulties. Meanwhile, techniques for the preservation, culture, and grafting of fetal neurons in humans have been developed and have been used in the treatment of Parkinson's disease. These procedures could readily be transferred to the treatment of other neurodegenerative diseases that cause significant morbidity, but ethical, legal, and religious considerations must be taken into account. All these efforts promise novel and improved management of inborn neurometabolic errors.

Animals↗
PubMed1992

Response of 6-pyruvoyl-tetrahydropterin synthase deficiency to tetrahydrobiopterin.

We have given tetrahydrobiopterin (BH4) in doses ranging from 2.5 to 20 mg/kg/day, each for a duration of 5 days to three patients with 6-pyruvoyltetrahydropterin synthase deficiency. As small a dose as 2.5 mg/kg/day BH4 reduced the blood phenylalanine to normal levels. However, the required dose of BH4 to reduce neopterin and to increase urine biopterin was 5 to 10 mg/kg/day, while 20 mg/kg/day was required for biopterin to appear in cerebrospinal fluid. The results suggest that BH4 effectively reduces endogenous neopterin synthesis. The dose of BH4 needed to normalize liver phenylalanine hydroxylase is one eighth to one fourth that required for normal neurotransmitter metabolism in the central nervous system.

Alcohol Oxidoreductases↗