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D Lindhout

Publications and source records attributed to D Lindhout.

At least 55 records · Page 3Linked to original sources
PubMed1998

A novel frameshift mutation 840delA and a novel polymorphism D203A in the steroidogenic acute regulatory protein gene in a Japanese patient with congenital lipoid adrenal hyperplasia. Mutations in brief no. 117. Online.

Congenital lipoid adrenal hyperplasia (CLAH) is an autosomalrecessive disorder characterized by impaired production of all steroids including glucocorticoids, mineralocorticoids and sexsteriods. It has recently been reported that mutations in the steriodogenic acute regulatory protein (StAR) gene cause CLAH. We analyzed the StAR gene in a Japanese patient with CLAH. The patient was revealed to be a compound heterozygote bearing a nonsense mutation Q258X, changing codon 258 (CAG) encoding Gln to the stop codon TAG, and a novel framshift mutation 840delA resulting from deletion of one of the three adenosines normally present in codon 238 (AAA), thus leading to a frameshift after codon 237 (Thr) in the StAR gene. The patient was also revealed to be homozygous for a novel missense point mutation D203A, changing codon 203 (GAC) encoding Asp to GCC encoding Ala in the StAR gene. To elucidate the significance of the D203A mutation, we analyzed the StAR gene sequence in twenty normal subjects, and found that all of them were homozygous for the D203A mutation, indicating that the D203A mutation is an innocent polymorphism. In conclusion, we have identified a novel frameshift mutation 840delA which seems to cause 840delA and the first polymorphism D203A in the human StAR gene.

Adrenal Hyperplasia, Congenital↗
PubMed1998

Psychomotor development in children with triphalangeal thumbs. A preliminary study.

In order to explore the influence of an isolated congenital hand malformation on psychomotor development, we performed an exploratory, observational study on 18 children with triphalangeal thumbs. The investigative procedure consisted of a hand function examination, a semi-structured interview with the mother about the development of the child, the so-called "Hand test", and the "Child Behaviour Check List". Our observations suggest specific developmental difficulties in fine motor skills and language development, but the children showed no signs of behavioural psychopathology.

Adolescent↗
PubMed1998

Genetics of limb development and congenital hand malformations.

The vertebrate limb bud develops along three different axes: proximodistal, anteroposterior, and dorsoventral. Several genetic factors responsible for control of each of the three limb axes have been identified. The genes involved interact in complex feedback loops to achieve proper arrangement and differentiation of tissues. Most of the available information on limb development and patterning has come from studies carried out in the lower vertebrates. In recent years, an increasing number of studies have been unraveling the genetic basis of human hand malformation phenotypes. At present, genes responsible for preaxial polydactyly, split hand/split foot malformation, and brachydactyly type C have been localized, and the gene responsible for synpolydactyly has been identified. In this paper, we present an overview of the genetic factors involved in limb development, followed by summarized discoveries in the genetics of human congenital hand malformations.

Arm↗
PubMed1998

Familial cylindromatosis mimicking tuberous sclerosis complex and confirmation of the cylindromatosis locus, CYLD1, in a large family.

A large Dutch family had been known for many years to be affected with skin tumours labelled as adenoma sebaceum, which were inherited in an autosomal dominant fashion. Since this skin sign is considered pathognomonic for tuberous sclerosis complex, the condition in the family was labelled accordingly, in the absence of further clinical features of tuberous sclerosis complex-like mental retardation or epilepsy. The skin changes started at early puberty with small eruptions around the nose and progressed to larger tumours, with considerable variation in severity. Some affected members had required plastic surgical reconstruction following excision. Linkage analysis in this family was performed for the two chromosomal regions involved in tuberous sclerosis complex on chromosomes 9q34 and 16p13, but no positive linkage was found. On critical re-evaluation of the clinical and pathological data and renewed assessment, the working diagnosis was changed to autosomal dominant cylindromatosis. The recently published candidate region for cylindromatosis on chromosome 16q12-13 was subsequently proven to be positively linked with a lod score of 3.02 with marker D16S308. Review of pathological specimens confirmed the diagnosis of cylindromatosis. DNA analysis of tumour tissue showed loss of heterozygosity for the cylindromatosis CYLD1 locus. These results confirm the candidate locus for cylindromatosis on chromosome 16q12-13.

Adenoma↗
PubMed1997

Identification of the tuberous sclerosis gene TSC1 on chromosome 9q34.

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the widespread development of distinctive tumors termed hamartomas. TSC-determining loci have been mapped to chromosomes 9q34 (TSC1) and 16p13 (TSC2). The TSC1 gene was identified from a 900-kilobase region containing at least 30 genes. The 8.6-kilobase TSC1 transcript is widely expressed and encodes a protein of 130 kilodaltons (hamartin) that has homology to a putative yeast protein of unknown function. Thirty-two distinct mutations were identified in TSC1, 30 of which were truncating, and a single mutation (2105delAAAG) was seen in six apparently unrelated patients. In one of these six, a somatic mutation in the wild-type allele was found in a TSC-associated renal carcinoma, which suggests that hamartin acts as a tumor suppressor.

Amino Acid Sequence↗
PubMed1997

The Dutch Uniform Multicenter Registration system for genetic disorders and malformation syndromes.

In medical genetics, several systems are used to classify and code genetic disorders for the purpose of automated registration. In the Netherlands, a genetic diagnosis code system has been developed that links a unique four-digit code to a principal description and all current synonyms. The main goal of this coding system is to enable nationwide uniformity of coding, without losing access to information stored in the past, identified by the ICD/BPA code (the International Classification of Diseases as adapted by the British Paediatric Association) and/or the MIM code (McKusick's classification in Mendelian Inheritance in Man). To this effect, the Dutch diagnosis code is cross-referenced with the 2 pre-existing classification systems. Developments in medical genetics make regular updates of all coding systems necessary. In the Netherlands, new diagnosis codes are assigned centrally to preserve uniformity and distributed periodically to all 8 clinical genetic centers. Diagnosis codes are assigned in numerical order of inclusion, enabling quick and easy updates. It is possible to include subclassifications of disorders according to pattern of inheritance, gene location, and gene mutations and to cover all disorders and disorder subtypes which are not clearly distinguished by the 2 pre-existing classification systems. The architecture of the coding system is suitable for international use. It offers a practical solution for clinical geneticists in need of a coding system suitable for clinical use. The use of the diagnosis code will also facilitate reliable comparison of data and nationwide genetic epidemiological studies.

Congenital Abnormalities↗
PubMed1997

Mutations involving the transcription factor CBFA1 cause cleidocranial dysplasia.

Cleidocranial dysplasia (CCD) is an autosomal-dominant condition characterized by hypoplasia/aplasia of clavicles, patent fontanelles, supernumerary teeth, short stature, and other changes in skeletal patterning and growth. In some families, the phenotype segregates with deletions resulting in heterozygous loss of CBFA1, a member of the runt family of transcription factors. In other families, insertion, deletion, and missense mutations lead to translational stop codons in the DNA binding domain or in the C-terminal transactivating region. In-frame expansion of a polyalanine stretch segregates in an affected family with brachydactyly and minor clinical findings of CCD. We conclude that CBFA1 mutations cause CCD and that heterozygous loss of function is sufficient to produce the disorder.

Alleles↗
PubMed1997

Partial cosegregation of familial hemiplegic migraine and a benign familial infantile epileptic syndrome.

PURPOSE: We studied a large Dutch-Canadian family, in which two very rare hereditary paroxysmal neurologic disorders, familial hemiplegic migraine (FHM) and a "benign familial infantile epileptic syndrome" concur and partially cosegregate. FHM is a dominantly inherited subtype of migraine with attacks of hemiparesis, linked to chromosome 19p13 in 50% of the families tested. Recently mutations in a brain-specific P/Q-type Ca2+ channel alpha1 subunit gene (CACNL1A4) were identified in families with chromosome 19-linked FHM. The infantile epileptic syndrome resembles to two other dominantly inherited benign epilepsies occurring in the first year of life, benign familial neonatal convulsions (BFNC), assigned to chromosomes 20q13.2 and 8q, and benign infantile familial convulsions (BIFC), as yet unlinked. METHODS: Linkage analysis was performed for the known locations of FHM and BFNC. The question whether the two conditions in this family can be caused by a single gene defect was addressed by additional linkage analysis. RESULTS: We excluded linkage of the infantile convulsions to markers on chromosome 20q13.2, 8q, or 19p13. This indicates the existence of a third locus for benign familial convulsions in the first year of life. Linkage of FHM to these markers was not formally excluded but seems very unlikely. Statistical analysis of whether, in this family, both conditions are caused by a single gene defect was inconclusive. CONCLUSIONS: We describe a "benign familial infantile epileptic syndrome" with attacks of FHM at a later age. Further genetic studies in this family may help to unravel the genetic basis of epilepsy or migraine or both.

Age of Onset↗
PubMed1997

Maternal use of antiepileptic drugs and the risk of major congenital malformations: a joint European prospective study of human teratogenesis associated with maternal epilepsy.

PURPOSE: To quantify the risks of intrauterine antiepileptic drug (AED) exposure in monotherapy and polytherapy. METHODS: Data from five prospective European studies totaling 1,379 children were pooled and reanalyzed. Data were available for 1,221 children exposed to AED during pregnancy and for 158 children of unexposed control pregnancies. RESULTS: Overall, when comparing a subgroup of 192 children exposed to AED with 158 children of matched nonepileptic controls, there was an increased risk of major congenital malformations (MCA) in children exposed to AED during gestation [relative risk (RR) 2.3; 95% confidence interval (CI): 1.2-4.7]. A significant increase in risk was found for children exposed to valproate (VPA) (RR 4.9; 95% CI: 1.6-15.0) or carbamazepine (CBZ) (RR 4.9; 95% CI: 1.3-18.0) in monotherapy. When comparing different AED regimens during all 1,221 pregnancies, risks of MCA were significantly increased for the combination of phenobarbital (PB) and ethosuximide (RR 9.8; 95% CI: 1.4-67.3) and the combination of phenytoin, PB, CBZ, and VPA (RR 11.0; 95% CI: 2.1-57.6). Offspring of mothers using > 1,000 mg VPA/day were at a significantly increased risk of MCA, especially neural tube defects, compared to offspring exposed < or =600 mg VPA/day (RR 6.8; 95% CI: 1.4-32.7). No difference in risk of MCA was found between the offspring exposed to 601-1,000 mg/day and < or =600 mg/day. CONCLUSIONS: This reanalysis shows that VPA is consistently associated with an increased risk of MCA in babies born to mothers with epilepsy. Significant associations were also observed with CBZ. Larger prospective population-based studies are needed to evaluate the risks of many other less frequently prescribed treatment regimens, including newly marketed AEDs.

Abnormalities, Drug-Induced↗
PubMed1997

Metacarpophalangeal pattern (MCPP) profile analysis in a family with triphalangeal thumb.

Triphalangeal thumb (TPT) is a rare congenital disorder characterised by a long, finger-like thumb with three phalanges instead of two. It can occur as an isolated defect, in association with other abnormalities of the hands and feet, or as a part of a syndrome. Sporadic cases have been described, but it is usually inherited as an autosomal dominant trait. In order to examine skeletal morphology in different phenotypic variations of this disorder, we performed metacarpophalangeal pattern profile analysis in one kindred with this disorder. A characteristic profile occurred in all affected people, based on the individual lengthening or shortening of the thumb bones. Comparison of the affected and unaffected people from this family with people with a different genetic background suggests that the described profile is specific for TPT and could be used as a helpful diagnostic tool in syndromes which include TPT.

Chromosome Aberrations↗
PubMed1996

Familial hemiplegic migraine and episodic ataxia type-2 are caused by mutations in the Ca2+ channel gene CACNL1A4.

Genes for familial hemiplegic migraine (FHM) and episodic ataxia type-2 (EA-2) have been mapped to chromosome 19p13. We characterized a brain-specific P/Q-type Ca2+ channel alpha1-subunit gene, CACNL1A4, covering 300 kb with 47 exons. Sequencing of all exons and their surroundings revealed polymorphic variations, including a (CA)n-repeat (D19S1150), a (CAG)n-repeat in the 3'-UTR, and different types of deleterious mutations in FHM and EA-2. In FHM, we found four different missense mutations in conserved functional domains. One mutation has occurred on two different haplotypes in unrelated FHM families. In EA-2, we found two mutations disrupting the reading frame. Thus, FHM and EA-2 can be considered as allelic channelopathies. A similar etiology may be involved in common types of migraine.

Base Sequence↗
PubMed1996

An insulin receptor mutant (Asp707 --> Ala), involved in leprechaunism, is processed and transported to the cell surface but unable to bind insulin.

We have identified a homozygous mutation near the carboxyl terminus of the insulin receptor (IR) alpha subunit from a leprechaun patient, changing Asp707 into Ala. Fibroblasts from this patient had no high affinity insulin binding sites. To examine the effect of the mutation on IR properties, the mutant IR was stably expressed in Chinese hamster ovary cells. Western blot analysis and metabolic labeling showed a normal processing of the mutant receptor to alpha and beta subunits. No increase in high affinity insulin binding sites was observed on Chinese hamster ovary cells expressing the mutant receptor, and also, affinity cross-linking of 125I-labeled insulin by disuccinimidyl suberate to these cells failed to label the mutant alpha subunit. Biotinylation of cell surface proteins by biotin succinimidyl ester resulted in efficient biotinylation of the mutant IR alpha and beta subunits, showing its presence on the cell surface. On solubilization of the mutant insulin receptor in Triton X-100-containing buffers, 125I-insulin was efficiently cross-linked to the receptor alpha subunit by disuccinimidyl suberate. These studies demonstrate that Ala707 IR is normally processed and transported to the cell surface and that the mutation distorts the insulin binding site. Detergent restores this site. This is an example of a naturally occurring mutation in the insulin receptor that affects insulin binding without affecting receptor transport and processing. This mutation points to a major contribution of the alpha subunit carboxyl terminus to insulin binding.

Abnormalities, Multiple↗
PubMed1996

A mutation which disrupts the hydrophobic core of the signal peptide of bilirubin UDP-glucuronosyltransferase, an endoplasmic reticulum membrane protein, causes Crigler-Najjar type II.

Crigler-Najjar (CN) disease is caused by a deficiency of the hepatic enzyme, bilirubin UDP-glucuronosyltransferase (B-UGT). We have found two CN type II patients, who were homozygous for a leucine to arginine transition at position 15 of B-UGT1. This mutation is expected to disrupt the hydrophobic core of the signal peptide of B-UGT1. Wild type and mutant B-UGT cDNAs were transfected in COS cells. Mutant and wild type mRNA were formed in equal amounts. The mutant protein was expressed with 0.5% efficiency, as compared to wild type. Mutant and wild type mRNAs were translated in vitro. Wild type transferase is processed by microsomes, no processing of the mutant protein was observed.

Amino Acid Sequence↗
PubMed1996

Identification of a nonsense mutation at the 5' end of the TSC2 gene in a family with a presumptive diagnosis of tuberous sclerosis complex.

Tuberous sclerosis complex (TSC) is an autosomal dominantly inherited disease with a high mutation rate. It is clinically a very variable disorder and hamartomas can occur in many different organs. TSC shows genetic heterogeneity; one gene, TSC1, is on chromosome 9q34, and the second gene, TSC2, on chromosome 16p13.3. Clinical criteria for diagnosis have been established, but diagnosis of patients with minimal expression of the disease can be very difficult. In children the phenotype is often incomplete or not fully assessable. Hence mildly affected subjects, at risk for severely affected offspring, may remain undiagnosed. The detection of (small) mutations in the tuberous sclerosis gene located on chromosome 16 (TSC2) has recently become possible and may be helpful in the diagnosis of ambiguous cases. To our knowledge, this is the first report of a point mutation in the TSC2 gene in a familial case of tuberous sclerosis. A nonsense mutation was detected in a family in which the father had only minor signs hinting at tuberous sclerosis. The son had multiple cardiac tumours and white patches, but full clinical investigation was impossible in this child. This case illustrates that mutation analysis can contribute to a diagnosis of tuberous sclerosis in families with an incomplete phenotype.

Adult↗
PubMed1996

Majority of hMLH1 mutations responsible for hereditary nonpolyposis colorectal cancer cluster at the exonic region 15-16.

Hereditary nonpolyposis colorectal cancer (HNPCC) is a common autosomal dominant cancer susceptibility condition. Inherited mutations in at least four DNA mismatch repair genes, hMSH2, hMLH1, hPMS1, and hPMS2, are known to cause HNPCC. In this study we used denaturing gradient gel electrophoresis (DGGE) to screen for hMLH1 mutations in 34 unrelated HNPCC families (30 Dutch, 3 Italian, and 1 Danish). Ten novel pathogenic germ-line mutations (seven affecting splice sites, two frameshifts, and one in-frame deletion of a single amino acid) have been identified in 12 (35%) of these families. In a previous study, hMSH2 mutations were found in 21% of the same families. While the spectrum of mutations at the hMSH2 gene among HNPCC patients appears heterogeneous, a cluster of hMLH1 mutations has been found in the region encompassing exons 15 and 16, which accounts for 50% of all the independent hMLH1 mutations described to date and for > 20% of the unrelated HNPCC kindreds here analyzed. This unexpected finding has a great practical value in the clinical scenario of genetic services.

Adaptor Proteins, Signal Transducing↗
PubMed1996

Genetic aspects of polydactyly.

The early limb development follows the similar pattern in all vertebrates since different species develop using the same regulatory genes in the formation of the body plan. Some of these genes remained well conserved during evolution and can be traced back as far as Drosophila--while some others changed their structure or developed new functions. This is why the limbs from different animals still look different from one another. However, all existing tetrapods have, like Homo Sapiens, limbs with five, or fewer digits. It has been argued that the interplay of the factors controlling the patterning and differentiation during the embryonal limb development can provide five distinct "genotypes" allowing development of only five different digits. This would imply that the Greek definition of polydactyly, namely "duplication of the finger or a part of it", is correct, not only in morphological but also in a genetical sense. Genes involved in the determination of the outline of the limb are candidates for disorders like polydactyly and syndactyly. Recently, we have localised the gene for triphalangeal thumb (TPT) on chromosome 7q. As almost 50% of our patient population also had rudimentary postaxial polydactyly and/or syndactyly, the interesting question arose whether the TPT gene also was responsible for isolated post-axial polydactyly. Our preliminary evidence suggests, however, that different gene(s) are involved in the pathomorphogenesis of postaxial polydactyly. Studies of human congenital hand malformations--combined with genetic studies in lower vertebrates--will help us to understand not only the molecular basis of these disorders, but also to get insight into the fascinating mechanisms involved in the normal development of the human hand.

Animals↗