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Biomedical subjects

K Hongell

Publications and source records attributed to K Hongell.

12 recordsLinked to original sources

Trisomy 13 in the mouse.

The fetal development of mice trisomic for chromosome 13 (Ts 13) was investigated. Trisomic fetuses were obtained from the progeny of male mice heterozygous for the two Robertsonian translocation chromosomes Rb (11.13)4Bnr and Rb (6.13)3Rma mated to "all acrocentric" NMRI females. Trisomic fetuses were found at all stages between days 12 and 19 of gestation (vaginal plug day counted as day 1). The frequency of trisomy was 24.8% of all surviving implants. The frequency of Ts decreased slightly but not significantly with progressing pregnancy. In eight newborn litters, two dead and four living trisomic newborns (13.6%) were found. The latter died within a few hours after birth. The most conspicuous features of Ts 13 fetuses were their small size and a marked hypoplasia as compared with their normal euploid in utero mates. The weight of the the trisomic fetuses and that of their placentas was significantly lower than of the normal controls at all stages studied. The general developmental delay and the delay of the ossification of Ts 13 fetuses were about 1 to 11/2 days. Cleft palate was observed in 86% of the Ts 13 fetuses. Edema developed in the neck and back of the trisomic fetuses from day 14 on; this disappeared after day 17. It is suggested that the hypoplasia and general retardation of growth found in trisomy 13 and in other autosomal trisomies, as well as the more or less specific palatal and cardiovascular malformations in this disorder, may be caused by impaired proliferation of trisomic cells. This postulated impairment of cell growth may also affect the fetal part of the placenta.

Animals

Partial trisomy 15 and temporal lobe syndrome in a retarded girl without gross malformations.

A supernumerary small bisatellited chromosome was found in a girl with stunted growth and psychomotor retardation. The extra chromosome was identified as a deleted 15, del(15)(q21), with C-band positive heterochromatin and satellite-like appendages to the distal end of the long arm. This chromosome was the product of a translocation between a chromosome 15 and some other acrocentric chromosome, as shown by G-, C- and Q-banding and silver staining of the nucleolus organizer regions. The proposita had no gross phenotypic malformations. She had a small head, a high forehead, oblique palpebral fissures, bilateral enophthalmus, clinodactyly and simple dermatoglyphic patterns. She was autistic and suffered from epileptic seizures and expressive aphasia. The waking electroencephalogram revealed diffuse abnormalities; sleep recording showed focal spikes and sharp waves anteriorly on the left side. The pneumo-encephalogram showed microventriculy, an enlarged left temporal horn and some enlarged sulci in the right frontotemporal cortex. The prenatal influence of the chromosome anomaly is interpreted as being the primary cause of these disorders, neonatal asphyxia being a secondary contributing factor.

Abnormalities, Multiple

Two cases of an abnormal short arm of chromosome 8 (8p+) associated with mental retardation.

Morphologically similar chromosome anomalies, 8p+, were found in two inmates of an institution for the mentally retarded. Analysis of the G-and R-banding patterns showed that the first subject had a duplication of region p2 of chromosome 8; the second subject had an insertion of an unidentified chromosome segment at 8p11. Both subjects were severely mentally retarded. The physical malformations were more severe in the second subject than in the first, who had only minor signs. The dermatoglyphics are recorded.

Abnormalities, Multiple

Free trisomy 9P in elderly woman.

The karyotype 47,XX,+9p was observed in a 50-year-old mentally retarded woman with dysmorphic facies, severe cerebral malformations, limb deformities, retarded sexual maturation and deviating dermatoglyphs. Banding analysis showed the extra chromosome to be composed of 9p and the proximal part of 9q comprising a large secondary constriction. The breakage point is estimated as 9q13. Hemozygous large C bands were observed in both chromosomes No. 9 as well as in the extra chromosome. Clinically this case can be regarded as a pure 9p trisomy. The mechanism causing the syndrome is thought to be malsegregation of a deleted chromosome No. 9.

Abnormalities, Multiple