Acrofacial dysostosis in a patient with the TSC2-PKD1 contiguous gene syndrome.
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Abnormalities, Multiple↗
Biomedical subjects
M H Breuning
Publications and source records attributed to M H Breuning.
What do women really want to know? Motives for attending familial breast cancer clinics.
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Adolescent↗
Heterozygous truncating mutation in the human homeobox gene GSH2 has no discernable phenotypic effect.
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Amino Acid Sequence↗
Autosomal dominant polycystic kidney disease: modification of disease progression.
Autosomal dominant polycystic kidney disease is a common inherited disorder, which is characterised by the formation of fluid-filled cysts in both kidneys that leads to progressive renal failure. Mutations in two genes, PKD1 and PKD2, are associated with the disorder. We describe the various factors that cause variation in disease progression between patients. These include whether the patient has a germline mutation in the PKD1 or in the PKD2 gene, and the nature of the mutation. Detection of mutations in PKD1 is complicated, but the total number identified is rising and will enable genotype-to-phenotype studies. Another factor affecting disease progression is the occurrence of somatic mutations in PKD genes. Furthermore, modifying genes might directly affect the function of polycystins by affecting the rate of somatic mutations or the rate of protein interactions, or they might affect cystogenesis itself or clinical factors associated with disease progression. Finally, environmental factors that speed up or slow down progress towards chronic renal failure have been identified in rodents.
Animals↗
Cerebral microbleeds in CADASIL.
BACKGROUND: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary arteriopathy leading to recurrent cerebral infarcts and dementia. Intracerebral hemorrhage (ICH) has been described sporadically in patients with CADASIL, suggesting that the affected arteries in CADASIL are not bleed-prone. However, the presence of cerebral microbleeds, which often remain undetected on conventional MRI, has not been determined in CADASIL. OBJECTIVE: To determine whether cerebral vessels in patients with CADASIL are prone to microbleeding. METHODS: T2*-weighted gradient echo MRI, which is highly sensitive for visualizing microbleeds, was performed in patients with CADASIL and their family members (n = 63). Known risk factors for ICH were determined for all individuals. On an exploratory basis, the presence of cerebral microbleeds was correlated with demographic variables, vascular risk factors, disease progression, ischemic MR lesions, and genotype. RESULTS: Cerebral microbleeds were present in 31% of symptomatic CADASIL mutation carriers, predominantly in the thalamus. Vascular risk factors such as hypertension did not account for the microbleeds in these patients. Factors associated with microbleeds were age (p = 0.008), Rankin disability score (p = 0.017), antiplatelet use (p = 0.025), number of lacunae on MRI (p = 0.009), and the Arg153Cys Notch3 mutation (p = 0.017). After correction for age, only the Arg153Cys mutation remained significantly associated with the presence of microbleeds. CONCLUSION: Patients with CADASIL have an age-related increased risk of intracerebral microbleeds. This implies that they may have an increased risk for ICH, which should be taken into account in CADASIL diagnosis and patient management.
Adult↗
[Responsibility circumvented with a set time for medical record keeping].
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Family Practice↗
A mutation in SLC11A3 is associated with autosomal dominant hemochromatosis.
Hereditary hemochromatosis (HH) is a very common disorder characterized by iron overload and multi-organ damage. Several genes involved in iron metabolism have been implicated in the pathology of HH (refs. 1-4). We report that a mutation in the gene encoding Solute Carrier family 11, member A3 (SLC11A3), also known as ferroportin, is associated with autosomal dominant hemochromatosis.
Amino Acid Sequence↗
Mutation detection for exons 2 to 10 of the polycystic kidney disease 1 (PKD1)-gene by DGGE.
The PKD1-gene encodes a 14 kb transcript spanning a 50 kb genomic interval. Two-thirds of the gene is reiterated at another locus on the same chromosome. Using Long Range PCR with primers in intron 1 and exon 11, 6.8 kb PKD1 specific fragments were generated on genomic DNA. These products were used as templates for nested PCR's to screen exons 2-10 by Denaturing Gradient Gel Electrophoresis (DGGE). Upon analysis of 36 patients, a total of 11 different sequence variants were observed: A nonsense mutation in exon 2, a frameshift mutation in exon 8 and furthermore, two amino acid changes, two silent polymorphisms and five intronic variants.
Adult↗
New mutations in the neuronal ceroid lipofuscinosis genes.
Thirty-eight mutations and seven polymorphisms have recently been reported in the genes underlying the neuronal ceroid lipofuscinoses (NCLs) including 11 new mutations described here. A total of 114 mutations and 28 polymorphisms have now been described in the five human genes identified which cause NCL. Thirty-eight mutations are recorded for CLN1/PPT; 40 for CLN2/TTP-1, 31 for CLN3, four for CLN5, one for CLN8. Two mutations have been described in animal genes (cln8/mnd, CTSD). All mutations in NCL genes are contained in the NCL Mutation Database (http://www.ucl.ac.uk/NCL).
Child↗
Atypical HNPCC owing to MSH6 germline mutations: analysis of a large Dutch pedigree.
Hereditary non-polyposis colorectal cancer (HNPCC) is the most common genetic susceptibility syndrome for colorectal cancer. HNPCC is most frequently caused by germline mutations in the DNA mismatch repair (MMR) genes MSH2 and MLH1. Recently, mutations in another MMR gene, MSH6 (also known as GTBP), have also been shown to result in HNPCC. Preliminary data indicate that the phenotype related to MSH6 mutations may differ from the classical HNPCC caused by defects in MSH2 and MLH1. Here, we describe an extended Dutch HNPCC family not fulfilling the Amsterdam criteria II and resulting from a MSH6 mutation. Overall, the penetrance of colorectal cancer appears to be significantly decreased (p<0.001) among the MSH6 mutation carriers in this family when compared with MSH2 and MLH1 carriers (32% by the age of 80 v >80%). Endometrial cancer is a frequent manifestation among female carriers (six out of 13 malignant tumours). Transitional cell carcinoma of the urinary tract is also relatively common in both male and female carriers (10% of the carriers). Moreover, the mean age of onset of both colorectal cancer (MSH6 v MSH2/MLH1 = 55 years v 44/41 years) and endometrial carcinomas (MSH6 v MSH2/MLH1 = 55 years v 49/48 years) is delayed. As previously reported, we confirm that the pattern of microsatellite instability, in combination with immunohistochemical analysis, can predict the presence of a MSH6 germline defect. The detailed characterisation of the clinical phenotype of this kindred contributes to the establishment of genotype-phenotype correlations in HNPCC owing to mutations in specific mismatch repair genes.
Adult↗
Polycystin-1, the product of the polycystic kidney disease 1 gene, co-localizes with desmosomes in MDCK cells.
Polycystin-1 is a novel protein predicted to be a large membrane-spanning glycoprotein with an extracellular N-terminus and an intracellular C-terminus, harboring several structural motifs. To study the subcellular localization, antibodies raised against various domains of polycystin-1 and against specific adhesion complex proteins were used for two-color immunofluorescence staining. In Madine Darby canine kidney (MDCK) cells, polycystin-1 was detected in the cytoplasm as well as co-localizing with desmosomes, but not with tight or adherens junctions. Using confocal laser scanning and immunoelectron microscopy we confirmed the desmosomal localization. By performing a calcium switch experiment, we demonstrated the sequential reassembly of tight junctions, subsequently adherens junctions and finally desmosomes. Polycystin-1 only stained the membrane after incorporation of desmoplakin into the desmosomes, suggesting that membrane-bound polycystin-1 may be important for cellular signaling or cell adhesion, but not for the assembly of adhesion complexes.
Animals↗
[From gene to disease; from hemoglobin genes to thalassemia and sickle cell anemia].
Haemoglobinopathies are the commonest autosomal recessive diseases in men. Mutations on the alpha and beta genes clusters, located on chromosome 16 and 11 respectively, have been strongly selected in many populations by the increased chance of survival of carriers in areas infested with malaria tropica. Unfortunately many of these mutations in homozygous or compound heterozygous forms generate severe phenotypes such as sickle cell disease and beta-thalassaemia major. The population at risk for haemoglobinopathies is increasing in the industrialized areas of northern Europe. Without preventive measures a cumulative number of 1,000 severely affected patients can be expected in the Netherlands if information and carrier diagnostics are not efficiently offered at the GP level. A specialized laboratory for postnatal and prenatal diagnosis has been available in Leiden for more than 10 years now; however, couples at risk are only sporadically referred for counselling and/or prenatal diagnosis.
Anemia, Sickle Cell↗
Recurrent digital fibroma, focal dermal hypoplasia, and limb malformations.
Recurrent digital fibroma of infancy generally is considered a sporadic tumor of childhood. We describe the case of a mother with recurrent digital fibroma at a young age who gave birth to a daughter with focal dermal hypoplasia, coloboma of the iris and eyelids, anal atresia, and extensive limb malformations. When the infant was 3 months old, fibromas started to appear at the fingertips. The cases of three additional patients are described, with a similar combination of multiple digital fibromas, pigmented marks on the temporal region, and limb malformations. One of these patients has consanguineous parents. The clinical findings overlap partially with Gorlin-Goltz syndrome, which has been renamed by some authors "microphthalmia with linear skin defects" (MLS). Since the skin signs are clearly different, however-more like those of Setleis syndrome ("forceps mark" temporal dysplasia)-the patients described here seem to have a new combination of congenital malformations. Deletion of distal Xp, known to occur in some MLS patients, was not detected using cosmids in fluorescence in situ hybridization. This pattern of digital fibroma with congenital malformations seems to represent a new syndrome.
Abnormalities, Multiple↗
[From gene to disease: introduction].
The knowledge of the molecular basis of many diseases is expanding rapidly. Consequently, molecular pathophysiology is becoming an integral part of all medical specialisms. In the evaluation of the relation between genes and diseases many aspects have to be considered: clinical manifestations of disease, gene structure, structure and function of the molecule encoded by the gene and molecular epidemiology in order to dissect the impact of molecular alterations in the population. In the series 'From gene to disease' these clinical, molecular and epidemiological aspects will be described for a number of diseases.
Genetics, Medical↗
[From gene to disease; basic concepts].
The twenty-three pairs of chromosomes in the nuclei of human cells consist of four different components: the nucleotides adenosine, cytidine, guanosine and thymidine. Of this chromosomal DNA, 5% of the nucleotides owing to their sequence code for proteins. This involves first transcription of DNA to messenger RNA (mRNA) following which the coding part is spliced and transported from the nucleus. Translation of mRNA to amino acids takes place in the endoplasmatic reticulum. Mutations in the nucleotide sequence (deletion, insertion, duplication or substitution) lead to a change in the reading of the sequence resulting in the production of no or of different proteins (gain of function and loss of function, respectively) with possibly a disease as the consequence.
DNA↗
[From gene to disease; marenostrine and familial Mediterranean fever].
Familial mediterranean fever (FMF) is an autosomal recessive hereditary disorder associated with mutations in the gene on chromosome 16 encoding the protein pyrine (marenostrine). Marenostrine is thought to stimulate the production of an inactivator of a chemotactic factor (possibly C5a). The mutations result in ongoing inflammation, a hallmark of FMF. DNA diagnosis of FMF is operational in Leiden University, the Netherlands, for one year now.
Complement C5a↗
[Intracranial aneurysms and autosomal dominant polycystic kidney disease].
Three women aged 55, 47 and 40 years with polycystic kidney disease had several relatives with cystic kidneys, some of whom had died or been crippled after (presumably) a subarachnoid haemorrhage. Two of these patients had a haemorrhage from an aneurysm of a cerebral artery; after clipping of the vessel they recovered without sequelae. The third patient had magnetic resonance (MR) angiography performed, which revealed no aneurysm. The prevalence of intracranial, saccular aneurysms in patients with autosomal dominant polycystic kidney disease (ADPKD) is about 10%. ADPKD patients with questions about the risk of a subarachnoid haemorrhage should be informed about the need of blood pressure control and the possibility of screening by MR angiography. Diagnosed aneurysms can be treated neurosurgically or endovascularly. Since aneurysms develop in the course of life, screening as a rule is only necessary from the age of 20 years, and its repetition every 5 years should be considered.
Adult↗
Rubinstein-Taybi syndrome caused by a De Novo reciprocal translocation t(2;16)(q36.3;p13.3).
Rubinstein-Taybi syndrome (RTS) is a multiple congenital anomalies and mental retardation syndrome characterized by facial abnormalities, broad thumbs, and broad big toes. We have shown previously that disruption of the human CREB-binding protein (CBP) gene, either by gross chromosomal rearrangements or by point mutations, leads to RTS. Translocations and inversions involving chromosome band 16p13.3 form the minority of CBP mutations, whereas microdeletions occur more frequently (approximately 10%). Breakpoints of six translocations and inversions in RTS patients described thus far were found clustered in a 13-kb intronic region at the 5' end of the CBP gene and could theoretically only result in proteins containing the extreme N-terminal region of CBP. In contrast, in one patient with a translocation t(2;16)(q36.3;p13.3) we show by using fiber FISH and Southern blot analysis that the chromosome 16 breakpoint lies about 100 kb downstream of this breakpoint cluster. In this patient, Western blot analysis of extracts prepared from lymphoblasts showed both a normal and an abnormal shorter protein lacking the C-terminal domain, indicating expression of both the normal and the mutant allele. The results suggest that the loss of C-terminal domains of CBP is sufficient to cause RTS. Furthermore, these data indicate the potential utility of Western blot analysis as an inexpensive and fast approach for screening RTS mutations.
CREB-Binding Protein↗