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Biomedical subjects

L Tranebjaerg

Publications and source records attributed to L Tranebjaerg.

At least 91 records · Page 5Linked to original sources
PubMed1994

Early prenatal direct gene diagnosis of cystic fibrosis in a twin pregnancy and subsequent selective termination.

We present a case of prenatal diagnosis of cystic fibrosis (CF) in one twin at 11-12 weeks of gestation. The parents had previously had two children, one of whom is alive and healthy and one who died of CF at the age of 2 1/2 months. The parents were both known to be carriers of the delta F508 mutation. Chorionic villus sampling (CVS) was performed and direct gene analysis showed that one fetus was homozygous for the delta F508 mutation, while the other fetus did not have the mutation at all. Both fetuses had normal karyotypes. Selective termination was subsequently performed. The pregnancy continued without complications except for mild pre-eclampsia at term. The woman had a Caesarean section. The genetic diagnosis was confirmed after birth.

Abortion, Induced↗
PubMed1994

394delTT: a Nordic cystic fibrosis mutation.

In a systematic screening for mutations in the gene encoding the cystic fibrosis transmembrane regulator among Danish cystic fibrosis (CF) patients, we identified a mutation in exon 3 (394delTT); this mutation was found to be relatively common in Denmark. We therefore screened for 394delTT in Sweden and Norway, where it turned out to be the second most frequent mutation, accounting for 4% of all CF mutations. It also occurs with a high frequency in Finland, but has not been found in larger surveys of mutations in the CFTR gene. Thus, 394delTT seems to be a specific Nordic CF mutation.

Base Sequence↗
PubMed1994

Aspartylglucosaminuria in northern Norway: a molecular and genealogical study.

Aspartylglucosaminuria (AGU, McKusick 208400) is an autosomal recessive lysosomal storage disorder. Ninety percent of all patients are from Finland and only sporadic cases have been reported from elsewhere. In northern Norway, however, nine patients from seven families have been diagnosed with AGU. All these Norwegian patients were homozygous for the most prevalent Finnish AGU mutation (AGUFin) and show the polymorphism uniquely associated with AGUFin in Finland. Genealogical investigation of nine parents proved Finnish ancestry in all pedigrees. Therefore, AGU in Norway most likely resulted from immigration of Finnish carriers. These Finnish immigrants originated mostly from the Tornio valley area in northern Finland in a continuous immigration movement from 1700 to 1900. The majority settled in the western part of northern Norway, leading to a "cluster" of AGU in that particular area. The Finnish immigrants intermixed considerably with Lapps and these two ethnic origins should thus be considered as high risk groups for AGUFin in northern Norway.

Acetylglucosamine↗
PubMed1993

The gene for spondyloepiphyseal dysplasia (SEDL) maps to Xp22 between DXS16 and DXS92.

Previous linkage studies in X-linked spondyloepiphyseal dysplasia (SEDL) placed the gene in the region Xp22.2-p22.1 by linkage to DXS41. Here we have extended our earlier studies by analyzing 15 families with 13 markers from the Xp22 region. Pairwise linkage analysis revealed significant linkage of the SEDL to 8 markers from the Xp22.2-Xp22.1 region. Maximum lod scores were obtained with DXS207, tau max = 9.16 at theta max = 0.021 with confidence limits of 0.00-0.09, and DXS197, tau max = 7.98 at theta max = 0.00 with confidence limits of 0.00-0.06. The study of one recombinant in family 4 indicated that DXS 41 is more likely proximal to DXS92 than distal. Multipoint linkage results and analysis of recombination events indicated that the mutation responsible for SEDL is located in Xp22 between DXS 16 and DXS 92.

Chromosome Mapping↗
PubMed1993

Frequency of the delta F508 and exon 11 mutations in Norwegian cystic fibrosis patients.

We have searched for the delta F508 mutation in 77 Norwegian cystic fibrosis patients. Of the 154 chromosomes tested, 93 (60%) carried the delta F508 mutation. Haplotypes at the D7S23 locus (KM19 and XV2C markers) were determined. Of 81 chromosomes with the F508 mutation, the B haplotype was found on 77. We found three patients with the G551D and one patient with the R553X mutation in exon 11 of the CFTR locus.

Cystic Fibrosis↗
PubMed1991

Deletion mapping of a retinal cone-rod dystrophy: assignment to 18q211.

Deletion of 18q211 was observed in a mentally retarded young man with electrophysiologically demonstrated cone-rod dystrophy, present since childhood. He had hypogonadism and a central postsynaptic hearing impairment. This is the first case of a chromosome deletion in a patient with a cone-rod dystrophy. Three patients with more distal deletions on chromosome 18 did not present retinal dystrophies. We suggest that one of the loci for cone-rod dystrophy may be located on chromosome 18 at q211-213. Reports of similar findings will be necessary for confirmation of this assumption.

Abnormalities, Multiple↗
PubMed1991

Physical mapping across the fragile X: hypermethylation and clinical expression of the fragile X syndrome.

The most common genetic cause of mental retardation after Down's syndrome, the fragile X syndrome, is associated with the occurrence of a fragile site at Xq27.3. This X-linked disease is intriguing because transmission can occur through phenotypically normal males. Theories to explain this unusual phenomenon include genomic rearrangements and methylation changes associated with a local block of reactivation of the X chromosome. Using microdissected markers close to the fragile site, we have been able to test these hypotheses. We present evidence for the association of methylation with the expression of the disease. However, there is no simple relationship between the degree of methylation and either the level of expression of the fragile site or the severity of the clinical phenotype.

Cell Line↗
PubMed1991

Immunoglobulin and complement studies in children with Schönlein-Henoch Syndrome and other vasculitic diseases.

In 35 children with Schönlein-Henoch Syndrome (SHS) serum IgG, IgM, and IgA concentrations were increased in 15%, 21%, and 44% of cases, respectively. Seven children with other vasculitic syndromes (VS) had normal serum Ig concentrations. Serum concentration of IgG subclass IgG1 was increased in 72% of children with SHS and 57% with VS. In SHS this was related to the presence of arthritis, but inversely related to nephritic symptoms. Only a few children had IgG subclasses IgG2, IgG3, or IgG4 concentrations outside the normal ranges. Platelet associated Ig (PAIg) was found in 75% of children with SHS or VS. In SHS the identification of increased amounts of PAIgG was related to the presence of nephritis. The serum concentration of properdin, a component of the alternative complement system, was reduced in 21% of children with SHS. This was related to the presence of abdominal symptoms or nephritis. No cases of retinal vasculitis was observed, but 4 of 22 children with SHS had punctuate retinal haemorrhages. SHS and VS may be clinical variations of the same syndrome. The immunological aspects indicate a close relationship with autoimmune diseases.

Adolescent↗
PubMed1991

Use of short sequence repeat DNA polymorphisms after PCR amplification to detect the parental origin of the additional chromosome 21 in Down syndrome.

The origin of nondisjunction in trisomy 21 has so far been studied using cytogenetic heteromorphisms and DNA polymorphisms using Southern blot analysis. Short sequence repeats have recently been described as an abundant class of DNA polymorphisms in the human genome, which can be typed using the polymerase chain reaction (PCR) amplification. We describe the usage of such markers on chromosome 21 in the study of parental origin of the additional chromosome 21 in 87 cases of Down syndrome. The polymorphisms studied were (a) two (GT)n repeats and a poly(A) tract of an Alu sequence within the HMG14 gene and (b) a (GT)n repeat of locus D21S156. The parental origin was determined in 68 cases by studying the segregation of polymorphic alleles in the nuclear families (either by scoring three different alleles in the proband or by dosage comparison of two different alleles in the proband). Our results demonstrate the usefulness of highly informative PCR markers for the study of nondisjunction in Down syndrome.

Alleles↗
PubMed1990

Clinical, cytogenetic, and molecular genetic characterization of two unrelated patients with different duplications of 21q.

We present 2 patients with dup(21q). Patient MP01 had mild mental retardation, facial findings characteristic of Down syndrome (DS), and a terminal duplication of chromosome 21. His karyotype was 46,XY,dup(21) (q22.1-qter). Patient MP03 had mild mental retardation, minor anomalies not characteristic of DS, and a duplication of the proximal long arm of chromosome 21, karyotype 46,XX,dup(21) (q11.2-q21.2). The patients were studied with single-copy DNA sequences from 20 loci on chromosome 21 to characterize the extent of the duplicated regions at the DNA level. DNA loci from D21S55 to COL6A1 were triplicated in patient MP01 while loci from D21S13 to D21S8 were triplicated in patient MP03. Our results support the hypothesis of a critical region of chromosome 21, which in triplicate is responsible for many of the facial changes associated with DS. Other genes outside this region may also contribute to other abnormalities observed in DS.

Adult↗
PubMed1989

Molecular genetic approach to the characterization of the "Down syndrome region" of chromosome 21.

The cytogenetically defined "Down syndrome region" of chromosome 21 has been characterized by DNA analysis in patients with partial trisomy 21 with or without Down syndrome features. Single-copy DNA sequences mapped on chromosome 21 were used to determine copy number by polymorphism and/or dosage analysis in the patients. Given our results, which in some patients were in disagreement with their cytogenetic descriptions, trisomy for locus D21S13 through locus D21S58 is excluded from significant contribution to many Down syndrome features. The minimal chromosome region necessary in triplicate to result in the Down syndrome phenotypes in the patients characterized includes the area from locus D21S55 to locus COL6A1. We could not analyze the region between loci D21S58 and D21S55 and between COL6A1 and 21qter at the molecular level due to a lack of DNA probes and, consequently, the contribution of these areas to a Down syndrome phenotype when present in three copies is unknown. The molecular cloning and mapping of chromosome 21 and the expansion of the patient population studied will likely result in a more precise molecular definition of the Down syndrome region.

Blotting, Southern↗
PubMed1989

Localization in man of fifteen DNA sequences within the chromosome segment 13q12-q22.

Fifteen human chromosome 13 specific DNA fragments, isolated from a lambda phage genomic library, were localized within the segment 13q12-q22. One was mapped to 13q12.1-q12.2, three to 13q12.3-q13.1, one to 13q14,1-q14.2, five to 13q14.1-q21.1, one to 13q21.1-q21.2, two to 13q21.2, and one to 13q22.1, and one to 13q22. The localization was performed by hybridization to Southern blots of a panel of human cell lines with overlapping deletions in 13q, and for three probes also by in situ hybridization to metaphase chromosomes.

Cell Line↗
PubMed1988

Interstitial deletion 13q: further delineation of the syndrome by clinical and high-resolution chromosome analysis of five patients.

Five patients with interstitial deletion 13q are reported. High-resolution chromosome banding established the diagnosis in two cases and stated the exact breakpoints in three remaining cases. All parents had normal chromosomes. An unequal and so far unexplained sex ratio of previously published and present cases was found: M:F = 1:2.75. Moderate to severe growth retardation was prominent in all patients. The patients were followed with psychological tests and growth data for 3-10 years. Mild to moderate mental retardation was present. Considerable phenotypic similarities were found in two patients with del(13)(q21.33 q31.3) and one with del(13)(q14.3q22.3). Repeat ophthalmological examinations showed no evidence of retinoblastoma in a male with del(13)(q13.1q21.1). In conclusion, the long-term study of five patients with interstitial deletion 13q, all evaluated with high-resolution banding, contributed to a more reliable mental and growth prognosis in such patients.

Abnormalities, Multiple↗
PubMed1987

Partial trisomy 3q syndrome inherited from familial t(3;9)(q26.1; p23).

A five-year-old girl was referred to prometaphase chromosome analysis because of mental retardation, facial dysmorphic features suggestive of Cornelia de Lange syndrome, cleft palate and additional minor congenital malformations of the cardiac system and fingers and toes. A familial balanced translocation (3;9)(q26.1; p23) was found. The karyotype of the proposita was 46,XX,der(9),t(3;9)(q26.1;p23). Thus the patient was trisomic for 3q26.1-qter and monosomic for 9p23-pter. The unbalanced chromosome constitution was not detected by standard Q-banding analysis shortly after birth. The karyotype was misdiagnosed as 46,XX,9(p+) in the proposita and her mother, and thought to be a normal variant of chromosome 9. The repeated cytogenetic study led to the diagnosis of the translocation and to the possibility of prenatal diagnosis in the translocation carriers. A survey of 22 published cases of dup(3q) showed that nearly 60% were secondary to familial balanced rearrangements with an excess of maternally derived abnormal chromosomes 3. Red blood cell galactose-1-phosphate-uridyltransferase (GALT) activity was normal in the patient, consistent with previous assignment of the gene locus for GALT to 9p13 (Shih et al. 1982).

Abnormalities, Multiple↗