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H D Bakker

Publications and source records attributed to H D Bakker.

At least 19 recordsLinked to original sources
PubMed2004

[From gene to disease; galactosemia and galactose-1-phosphate uridyltransferase deficiency].

Classical galactosaemia (Mendelian Inheritance in Man, no 230400) is an autosomal recessive disorder of galactose metabolism caused by a deficiency of the enzyme galactose-1-phosphate uridyltransferase (GALT). The GALT enzyme is responsible for the conversion of galactose-1-phosphate with UDP glucose to glucose-1-phosphate and UDP galactose. The gene encoding for GALT is located on chromosome 9p13. Patients present with hepatomegaly, liver failure, food intolerance, hypoglycaemia, muscle hypotonia, sepsis and cataract. Treatment involving the total restriction of lactose-containing foods is life-saving but many patients develop late complications such as problems of mental development, disorders of motor function, disorders of speech and hypergonadotrophic hypogonadism.

Galactosemias↗
PubMed2003

Plant sterols lower LDL cholesterol without improving endothelial function in prepubertal children with familial hypercholesterolaemia.

In adults with familial hypercholesterolaemia (FH), cholesterol lowering with statins has been shown to improve the endothelial function, a hallmark of early atherogenesis. Currently, therapeutic options for treating high cholesterol levels in FH children are limited. Plant sterols safely and effectively reduce serum cholesterol concentrations by inhibiting cholesterol absorption. Therefore, we evaluated the effect of plant sterols on cholesterol and vascular function in prepubertal children with FH. We included 41 children (5-12 years old) with FH in a double-blind crossover trial using spreads containing 2.3 g of plant sterols (mainly sitosterol and campesterol) per 15 g spread and a placebo spread for a 4-week period, separated by a 6-week washout period. Lipid levels and endothelial function were assessed after both 4-week treatment periods. Endothelial function was assessed as flow-mediated dilation (FMD) of the brachial artery using a wall tracking system. Data were compared to those of 20 healthy controls. Intake of 2.3 g plant sterols per day decreased total cholesterol (-11%) and low-density cholesterol (-14%) as compared to placebo spread in FH children. FH children treated with placebo spread were characterized by an impaired FMD compared to healthy control children (7.2% +/- 3.4% versus 10.1% +/- 4.2%, p < 0.005). However, the reduction of LDL in FH children did not improve FMD (placebo: 7.2% +/- 3.4% versus plant sterols: 7.7% +/- 4.1%). In conclusion, the present study shows a clear reduction of LDL cholesterol by plant sterol treatment. However, short-term plant sterol treatment does not improve the endothelial function in FH children.

Brachial Artery↗
PubMed2003

GLUT-1 deficiency without epilepsy--an exceptional case.

The GLUT-1 deficiency is a metabolic disorder caused by a defect in glucose transport across the blood-brain barrier as a result of a defect in the glucose-transport protein. Patients present with epileptic seizures, delayed development, ataxia and hypotonia, and in many cases acquired microcephaly. In most patients, treatment with a ketogenic diet proved to be successful in controlling the epilepsy. We report a 9-year-old boy with retardation and ataxia, but without epilepsy, caused by GLUT-1 deficiency, proven biochemically and by DNA analysis. Treatment with a medium-chain triglyceride ketogenic diet had a beneficial effect.

Ataxia↗
PubMed2003

Quality of life, anxiety and concerns among statin-treated children with familial hypercholesterolaemia and their parents.

AIM: To assess the quality of life, anxiety and concerns among statin-treated children with familial hypercholesterolaemia (FH) and their parents. METHODS: 69 FH children on statin therapy and 87 parents (51 families) participated in this study. Quality of life of the children, and anxiety levels of both the children and their parents, were investigated using self-report questionnaires. In addition, a questionnaire was designed to evaluate FH-specific concerns of these children and their parents on six different topics: 1, knowledge about FH; 2, experience of the disease; 3, family communication; 4, screening; 5, diet; and 6, experience of medication therapy. RESULTS: FH children and their parents reported no problems with regard to quality of life and anxiety. In contrast, the FH survey showed specific FH-related concerns. One-third of the children thought that FH can be cured, and 44% of the children suffered from the fact they have FH, but taking medication makes them feel safer (62%). The majority of the children kept a low cholesterol diet and more than 50% took care not to eat too much fat. Almost 38% of the parents experienced FH as a burden to their family and 79% suffered because their child had FH. CONCLUSION: These findings show that statin-treated children with FH and their parents did not report affected psychosocial functioning, but did show specific FH-related concerns.

Adolescent↗
PubMed2002

Structure of the human argininosuccinate synthetase gene and an improved system for molecular diagnostics in patients with classical and mild citrullinemia.

Deficiency of argininosuccinate synthetase (ASS) causes citrullinemia, an autosomal recessive inherited defect of the urea cycle. Most patients described so far have presented with the classical form of the disease. There are also patients with a mild form of citrullinemia in whom the exact molecular basis and clinical relevance are uncertain. Mutations in the human ASS gene have not yet been described in mildly affected or asymptomatic patients with citrullinemia. The genomic sequence of the human ASS gene is not precisely known making mutation analysis difficult. Here, the entire genomic DNA sequence and mutations in the ASS gene of patients with the classical and mild form of the disease are described. The mutations c.1168G-->A (G390R) and IVS13+5 G-->A and the novel mutation c.323G-->T (R108L) have been found to be associated with classical citrullinemia, whereas the novel mutations c.535T-->G (W179R), and c.1085G-->T (G362V) have been detected on alleles of the mildly affected patients. Thus, mutations found in the human ASS gene of asymptomatic children with biochemical abnormalities and in some cases enzymatically proven citrullinemia have allowed us to classify these cases as ASS-deficient patients. The elucidation of the structure of the human ASS gene has made possible the use of intronic primers for molecular analysis of patients with mild disease and the classical form, and provides another option for prenatal diagnostics in affected families with the severe type.

Amino Acid Sequence↗
PubMed2002

Clinical features of galactokinase deficiency: a review of the literature.

Galactokinase deficiency (McKusick 230200) is a rare autosomal recessive inborn error of galactose metabolism. Cataract and, rarely, pseudotumor cerebri caused by galactitol accumulation seem to be the only consistently reported abnormalities in this disorder. We performed a literature search to obtain information on the clinical spectrum of galactokinase deficiency. A total of 25 publications were traced describing 55 galactokinase-deficient patients. Cataract was reported in most patients. Clinical abnormalities other than cataract were reported in 15 (35%) out of 43 cases on which information was available. However, all symptoms were reported infrequently and a causal relationship with the galactokinase deficiency is unlikely. As cataract and pseudotumor cerebri appear to be the sole complications of galactokinase deficiency, the outcome for patients with galactokinase deficiency is much better than for patients with classical galactosaemia (McKusick 230400), a more common autosomal recessive disorder of galactose metabolism caused by galactose-1-phosphate uridyltransferase (GALT; EC 2.7.7.12) deficiency. Long-term follow-up of patients with this disorder has shown that, in spite of a severely galactose-restricted diet, most patients develop abnormalities such as a disturbed mental and/or motor development, dyspraxia and hypergonadotropic hypogonadism. Endogenous production of galactose has been considered an important aetiological factor. Although damage may well occur in utero, available evidence suggests that damage will continue after birth. Inhibition of galactokinase may then be a promising approach for controlling damage in GALT-deficient patients.

Carbohydrate Metabolism, Inborn Errors↗
PubMed2001

Human alpha-N-acetylgalactosaminidase (alpha-NAGA) deficiency: no association with neuroaxonal dystrophy?

Two new individuals with alpha-NAGA deficiency are presented. The index patient, 3 years old, has congenital cataract, slight motor retardation and secondary demyelinisation. Screening of his sibs revealed an alpha-NAGA deficiency in his 7-year-old healthy brother who had no clinical or neurological symptoms. Both sibs are homozygous for the E325K mutation, the same genotype that was found in the most severe form of alpha-NAGA deficiency presenting as infantile neuroaxonal dystrophy. Thus, at the age of 7 years the same genotype of alpha-NAGA may present as a 'non-disease' (present healthy case) and can be associated with the vegetative state (the first two patients described with alpha-NAGA deficiency). The clinical heterogeneity among the 11 known individuals with alpha-NAGA deficiency is extreme, with a 'non-disease' (two cases) and infantile neuroaxonal dystrophy (two cases) at the opposite sides of the clinical spectrum. The broad spectrum is completed by a very heterogeneous group of patients with various degrees of epilepsy/behavioural difficulties/psychomotor retardation (four patients) and a mild phenotype in adults without overt neurological manifestations who have angiokeratoma and clear vacuolisation in various cell types (three cases). These observations are difficult to reconcile with a straightforward genotype-phenotype correlation and suggest that factors or genes other than alpha-NAGA contribute to the clinical heterogeneity of the 11 patients with alpha-NAGA deficiency.

Cells, Cultured↗
PubMed1999

Genotype and phenotype in patients with dihydropyrimidine dehydrogenase deficiency.

Dihydropyrimidine dehydrogenase (DPD) deficiency is an autosomal recessive disease characterised by thymine-uraciluria in homozygous deficient patients and has been associated with a variable clinical phenotype. In order to understand the genetic and phenotypic basis for DPD deficiency, we have reviewed 17 families presenting 22 patients with complete deficiency of DPD. In this group of patients, 7 different mutations have been identified, including 2 deletions [295-298delTCAT, 1897delC], 1 splice-site mutation [IVS14+1G>A)] and 4 missense mutations (85T>C, 703C>T, 2658G>A, 2983G>T). Analysis of the prevalence of the various mutations among DPD patients has shown that the G-->A point mutation in the invariant splice donor site is by far the most common (52%), whereas the other six mutations are less frequently observed. A large phenotypic variability has been observed, with convulsive disorders, motor retardation and mental retardation being the most abundant manifestations. A clear correlation between the genotype and phenotype has not been established. An altered beta-alanine, uracil and thymine homeostasis might underlie the various clinical abnormalities encountered in patients with DPD deficiency.

Animals↗
PubMed1998

Familial mitochondrial DNA depletion in liver: haplotype analysis of candidate genes.

Two sons and one daughter of healthy consanguineous parents presented with fatal hepatic failure in association with severe depletion of mitochondrial (mt)DNA in liver; a third son is healthy. Other published cases of mtDNA depletion concern single members of a family, which excludes the use of haplotype analysis. In the family presented here, the inheritance of the genes for mitochondrial transcription factor A (mtTFA), nuclear respiratory factor 1 (NRF-1), mitochondrial single-stranded DNA-binding protein (mtSSBP), and endonuclease G (EndoG) was studied using microsatellite markers linked to these genes. The inheritance of the gene for mtDNA polymerase (pol gamma) was studied using a polymorphic CAG repeat present within the coding region of the gene. EndoG and mtSSBP were excluded, but mtTFA remains a candidate. Pol gamma or NRF-1 involvement would be compatible only with autosomal dominant inheritance. Coding sequence analysis of NRF-1 and mtTFA revealed no novel mutations in affected individuals.

Chromosomes, Human↗
PubMed1998

The success of dietary protein restriction in alkaptonuria patients is age-dependent.

Alkaptonuria is characterized by an increased urinary excretion of homogentisic acid, pigmentation of cartilage and connective tissues, and ultimately the development of inflammatory arthropathy. Various diets low in protein have been designed to decrease homogentisic acid excretion and to prevent the ochronotic pigmentation and arthritic lesions. However, limited information is available on the long-term beneficial effects of these diets. We reviewed the medical records of 16 patients aged 3-27 years (4 > 18 years) to ascertain the age of diagnosis, growth, development, social behaviour, signs of complications and longitudinal dietary compliance. The diagnosis of alkaptonuria was made at an average age of 1.4 years (2 months-4 years); following the diagnosis all patients were prescribed a diet with a protein content of 1.5 g/kg per day. All patients showed normal growth and development, and no major complications of the disease. Behavioural problems associated with poor dietary compliance emerged as the main problem. Dietary compliance decreased progressively with age. The effect of dietary protein restriction in homogentisic acid excretion was studied by fixing the amounts of protein in the diet at 1 g/kg per day and 3.5-5 g/kg per day during 8 days. Twelve patients, aged 4-27 years, participated in the investigation. Protein restriction resulted in a significantly lower excretion of homogentisic acid in the urine of children younger than 12 years (p < 0.01), whereas this effect was less obvious for adolescent and adult patients. The results suggest that restriction of protein intake may have a beneficial effect on alkaptonuric children; but continuation of this regimen to older age seems questionable and not practical.

Adolescent↗
PubMed1998

Iatrogenic isolated isoleucine deficiency as the cause of an acrodermatitis enteropathica-like syndrome.

We present two patients with a suspected inborn error of metabolism. A female newborn presented with dysmorphic features and convulsions. Metabolic screening suggested a defect in isoleucine degradation. Within 2 weeks after the introduction of an isoleucine-restricted diet, she developed a severe acrodermatitis enteropathica-like syndrome. The plasma level of isoleucine was low with a normal leucine/isoleucine ratio. The second patient, a female infant deficient in leucine as a result of a leucine-restricted diet, did not develop a dermatosis. Isoleucine is essential for normal growth and differentiation of keratinocytes and enterocytes. Deficiency of isoleucine, and not leucine or an imbalance in the leucine/isoleucine ratio, may result in an acrodermatitis enteropathica-like syndrome.

Acrodermatitis↗
PubMed1998

Mutations in the liver glycogen phosphorylase gene (PYGL) underlying glycogenosis type VI.

Deficiency of glycogen phosphorylase in the liver gives rise to glycogen-storage disease type VI (Hers disease; MIM 232700). We report the identification of the first mutations in PYGL, the gene encoding the liver isoform of glycogen phosphorylase, in three patients with Hers disease. These are two splice-site mutations and two missense mutations. A mutation of the 5' splice-site consensus of intron 14 causes the retention of intron 14 and the utilization of two illegitimate 5' splice sites, whereas a mutation of the 3' splice-site consensus of intron 4 causes the skipping of exon 5. Two missense mutations, N338S and N376K, both cause nonconservative replacements of amino acids that are absolutely conserved even in yeast and bacterial phosphorylases. We also report corrections of the PYGL coding sequence, sequence polymorphisms, and a partial PYGL gene structure with introns in the same positions as in PYGM, the gene of the muscle isoform of phosphorylase. Our findings demonstrate that PYGL mutations cause Hers disease, and they may improve laboratory diagnosis of deficiencies of the liver phosphorylase system.

Amino Acid Sequence↗
PubMed1998

MR imaging and proton spectroscopy in 3-hydroxy-3-methylglutaryl coenzyme A lyase deficiency.

Three patients with 3-hydroxy-3-methylglutaryl coenzyme A lyase deficiency were examined with MR imaging and proton MR spectroscopy. In two patients, both clinically normal, MR images showed a diffuse mild abnormality in signal intensity of the cerebral white matter, with multiple foci of more pronounced signal abnormality superimposed. In the third patient, who was clinically retarded and had a cerebral visual impairment, MR imaging showed, in addition to a diffuse signal abnormality of the cerebral white matter, atrophic scarring of the occipital lobes and abnormal signal intensity of the thalami and basal ganglia. It is highly probable that the additional lesions in the occipital lobes and basal nuclei were related to the episode of severe neonatal hypoglycemia the patient experienced. The MR spectroscopic abnormalities correlated with the degree of disease as evidenced by MR imaging.

Amino Acid Metabolism, Inborn Errors↗
PubMed1997

[Is detection and treatment of familial hypercholesterolemia indicated in children?].

Familial hypercholesterolaemia (FH) is a congenital metabolic disorder predisposing to severe atherosclerosis resulting in coronary heart disease sometimes even at early adult age. Children with FH lack the stigmata at physical examination and measuring the cholesterol level does not always enable the clinician to make the diagnosis. In about 70% of the cases, the diagnosis of FH in childhood can be made by means of molecular-biological examination, by demonstrating the underlying defect of the LDL cholesterol receptor gene. In the remaining cases, the combination of the positive family history for cardiovascular diseases and increased total cholesterol and LDL cholesterol levels should suggest the diagnosis of FH. Pharmaceutical agents inhibiting the cholesterol synthesis have been researched very little in children and are not registered in the Netherlands. Nevertheless, drug treatment of children with FH is advisable because of the better possibilities to make a definite diagnosis and the early occurrence of coronary heart disease. If this treatment were indicated before patients reach adult age, the question arises whether screening for FH of children in families in which this disorder prevails, should not be promoted more strongly.

Adolescent↗
PubMed1997

Macrocephaly, facial abnormalities, disproportionate tall stature, and mental retardation--a sib observation.

We report on two brothers with relatively short limbs, macrocephaly, high and narrow forehead, frontal upsweep of hairline, hypotelorism, broad but short ears, straight back, and mild hypermobility of all joints. Both were hypotonic neonatally and had developmental delay and behavior problems. Several of the manifestations were present in the father, too. A literature search failed to uncover any similar case.

Abnormalities, Multiple↗