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Biomedical subjects

M Mikkelsen

Publications and source records attributed to M Mikkelsen.

At least 109 records · Page 6Linked to original sources
PubMed1981

Chromosomes in the Cornelia de Lange syndrome.

This paper summarizes previous chromosomal studies in patients with the Cornelia de Lange syndrome showing abnormal karyotypes. We report on 45 cases of the Cornelia de Lange syndrome clinically examined by one of us (B.B.) and chromosomally studied using several different methods. Two abnormal karyotypes were found: a girl with a 45,X karyotype and a boy with a (13q14q) translocation which was also found in his phenotypically normal mother and maternal grandmother. Because of recent reports of the duplication 3q syndrome and Cornelia de Lange-like phenotypes, prometaphase chromosomes were studied in 31 patients. All karyotypes were normal. As there was an excess of boys among the younger patients, special examination for the fragile site on X(q28) was carried out. This abnormality was not found. Even though no patients with the dup(3q) syndrome were found among the Cornelia de Lange patients, chromosome studies are recommended especially in connection with genetic counselling. A recurrence rate of 2-5% must still be considered for the Cornelia de Lange syndrome.

Adolescent↗
PubMed1981

Partial deletion of the short arm of chromosome 3.

A case of deletion of the short arm of chromosome 3 (46,XY,del(3)(p253) is described. The patient is a youth of 18 years in an institution for the mentally retarded. Phenotypically, he presents congenital heart disease, hypertelorism, ptosis, epicanthus, blepharophimosis, strabismus, nystagmus, synophrys, low-set ears, frequent infections, epilepsy (abnormal EEG and grand mal seizures), "rocker bottom" feet, flat occiput and muscular hypotonia. The parents are healthy and with normal karyotypes. A silent allele in the GPT system was found in the mother, the propositus and 4 of the 5 siblings.

Abnormalities, Multiple↗
PubMed1981

Familial X-linked mental retardation and fragile X chromosomes in two Swedish families.

X-linked mental retardation (MR) associated with a fragile X chromosome was found in two Swedish families. The fragile X chromosome was demonstrated in 5/5 boys with mental retardation. Clinical data on four of these boys are presented. In one of the families, the mental retardation was associated with macro-orchidism, large hands and large, folded ears. In the other family, macro-orchidism was not seen, possible because the boys were younger. Fragile site X chromosomes were also seen in three obligate carriers. A summary of earlier published cases of X-linked MR associated with the fragile X chromosome is given.

Abnormalities, Multiple↗
PubMed1980

Non-disjunction in trisomy 21: study of chromosomal heteromorphisms in 110 families.

QM variants on chromosome 21 and silver staining of NOR regions were applied in the study of non-disjunction in 110 families from different parts of Denmark. In 76% of the families the study was informative. Paternal failures were observed in 11% on Funen as compared 23.5% on Zealand. In one family, crossing-over on the short arms of chromosome 21 in the mother and mitotic non-disjunction of chromosome 21 was observed. Maternal first meiotic error predominates in both high maternal and low maternal age. Also in paternal non-disjunction failures of first meiotic division predominate. Two maternally and one paternally originated cases of de novo translocations were observed.

Adolescent↗
PubMed1978

Small metacentric nonsatellited extra chromosome: report of five mentally retarded individuals and review of literature. Contribution to further delineation of a new syndrome.

Five mentally retarded male patients with a supernumerary small metacentric nonsatellited chromosome were found to have many clinical features in common. The face showed characteristic small crowded features, the bodily habitus was asthenic, and the hands and feet had minor abnormalities. Renal anomalies were present in two patients. One patient had a myelomeningocele. Cytogenetic studies employing Q, R, and C banding in four patients showed the small extra chromosome to have staining properties compatible with an isochromosome of the short arm of chromosome 18. A comparison with previous case reports suggests a new syndrome. However, the identity of the extra chromosome has not yet been determined.

Adolescent↗
PubMed1978

[Oligophrenia].

Explore the source record for details and available documents.

Adult↗
PubMed1978

Turner syndrome with rare karyotypes.

Five cases of Turner syndrome with rare karyotypes are presented. The spectrum of chromosomal findings ranges from a female karyotype with a deletion of the short arm of one X chromosome, to a normal male karyotype. The following karyotypes were found: one case with 46,XXp--; two cases with 45,X/46,X,r(X); one case with 45,X/47,XYY; and one case with 46,XY.

Adolescent↗
PubMed1978

The origin of the extra chromosome 21 in Down syndrome. Studies of fluorescent variants and satelite association in 26 informative families.

Studies of fluorescence and other chromosomal variants were informative in 26 out of 72 families. Maternal nondisjunction was found in 19 and paternal in 7 cases. Satellite association studies of these parents and 94 controls from the same age group showed a highly significant increase in the satellite association index (AI) for chromosome 21 in the parents where the nondisjunctional event had taken place. The AI was also higher for chromosome 14. In addition, the parents who produced the normal gametes had significantly higher AI's for some acrocentrics than the controls. Exogenous factors increasing satellite association cannot be ruled out. The number of 21-21 association was significantly increased in the parents with nondisjunction in meiosis 1. The results indicate that satellite association may play a role in the etiology of Down syndrome.

Child, Preschool↗
PubMed1977

Inhibition of the development of Q-bands on human chromosomes by netropsin.

Netropsin, an oligopeptide-type basic antibiotic, having exclusively A-T-specific DNA-binding affinity and situating itself into the minor groove of the double helix, represses the development of Q-bands if human chromosome preparations are treated with it before quinacrine mustard staining. The most probable interpretation of this effect is that netropsin interferes with the intercalation of the dye molecules. It is assumed this phenomenon supports the hypothesis that quinacrine mustard binds preferentially to A-T-rich sequences of DNA in the metaphase chromosomes.

Adenosine↗
PubMed1977

Amniocentesis in prenatal diagnosis. A controlled series of 78 cases.

The outcome of 78 pregnancies, monitored by second trimester amniocentesis for prevention of genetic disease, and the outcome of an equal number of matched controls are reported. The controls were selected from the same obstetrical department, among the same population,and were matched for age, number of previous children, abortions and stillbirths. No significant difference was found in Apgar score, birth-weight and length, duration of pregnancy, placenta condition or malformation.

Abortion, Spontaneous↗
PubMed1977

Paternal age effect in Down's syndrome.

Increasing incidence of Down's syndrome with advancing paternal age for given maternal age has been demonstrated. Comparisons are made between an almost complete Down's syndrome sample from the Copenhagen Metropolitan Area and a randomly selected sample of births from the same area and the same time period. Men above 55 years have a significantly increased risk of getting children with Down's syndrome.

Adolescent↗