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Biomedical subjects

G Schwanitz

Publications and source records attributed to G Schwanitz.

133 records · Page 8Linked to original sources
PubMedDate not supplied

Formation of uniparental disomy 7 delineated from new cases and a UPD7 case after trisomy 7 rescue. Presentation of own results and review of the literature.

Maternal uniparental disomy for the entire chromosome 7 (matUPD7) has been reported several times in Silver-Russell syndrome (SRS) and growth-restricted patients. Here we present our results from the analysis of an abortion with confined placental mosaicism (CPM) for trisomy 7 which showed a maternal meiotic origin of the trisomy in the placenta and rescue to maternal UPD7 in foetal membrane. Furthermore, two newly detected SRS cases with maternal UPD7 revealed isodisomy and partial heterodisomy, respectively. Summarising these results with those published previously on the origin of UPD7, similar numbers of isodisomy (n=11) and cases with complete or partial heterodisomy (n=12) have been reported. In respect to the different formation mechanisms of UPD, complete isodisomy should be the result of a post-zygotic mitotic segregation error, whereas heterodisomic UPDs should be caused by trisomic rescue after meiotic non-disjunction events. In maternal UPD7, 50% of cases seem to be caused by post-zygotic mitotic segregation errors, which is similar to the situation in trisomy 7. This result corresponds to the situation in trisomy 8 but is in contrast to observations in the frequent aneuploidies. Thus, the different findings in these aberrations reflect the presence of multiple factors that act to ensure normal segregation, varying in importance for each chromosome.

Abnormalities, Multiple↗
PubMedDate not supplied

[Bardet-Biedl syndrome: aspects of nephro-urology and human genetics].

Bardet-Biedl syndrome is a genetically heterogeneous autosomal recessive complex of features in which five gene loci have been described up to now. The diagnosis of this rare syndrome is based on the main manifestations hypogonadism, age-dependent increasing obesity and reduction of renal function, age-dependent progressive retinal degeneration with blindness as well as postaxial polydactyly and mental retardation. The life expectancy is short. Problems of early diagnostics, secondary hyperparathyroidism as well as surgical reconstruction of the genitals and kidney replacement therapy are discussed.

Adolescent↗
PubMedDate not supplied

[Non-immunologic hydrops fetalis (NIHF)--case report of double partial trisomy 15q and 17q resulting from familial translocation 15/17 and cytogenetic findings in 50 cases with hydrops fetalis].

We report the first case of non-immune hydrops fetalis (NIHF) with trisomy 15q11/17q22.5 resulting from a familial translocation 15/17. Furthermore the cytogenetic findings of 50 cases with hydrops fetalis are presented. Of the 30 cytogenetic analyzable cases 7 showed chromosomal abnormalities (4x45,X; 2x47,XY,+21; 1x47,XY,+13). In every case of NIHF a chromosomal analysis should be performed if possible from different tissues.

Chromosomes, Human, Pair 15↗
PubMedDate not supplied

[Gonadal dysgenesis--possible variation of clinical, hormonal, cytogenetic and histologic findings].

Errors of gonadal differentiation are influencing the sex differentiation on the whole in man. Since the methods in clinical cytogenetics improved, an exact chromosome investigation became possible, which enables the necessary therapy, the appropriate medical and psychological care, and the genetic counselling. Regarding our own observations, general surveys on the frequencies of the different syndromes and on the occurrence of the single clinical symptoms are given.

Adolescent↗
PubMedDate not supplied

[Undescended testis and hypospadia in sex chromosomal aberrations].

If hermaphrodite genitals are present in the patient or a higher degree of hypospadia is shown with maldescensus testis, a chromosomal disorder must be considered as one potential cause of the anomaly. The case report of a child with cryptorchidism on the right, inguinal testis on the left and penoscrotal hypospadia is presented as an example. A mosaic karyotype 45, X/46, X, idic (Yp) was diagnosed in this patient after chromosomal analysis. The cell line with the isodicentric Y chromosome could be demonstrated in about 90% of the lymphocytes, but only in 7% of the fibroblasts of the preputium. A derivative Y could not be detected in interphase nuclei in the buccal mucosa, i.e. only the cell line with monosomy X was presented. There was thus chromosomal mosaicism with unequal tissue involvement and a high potential for malignant transformation. Guidelines of pediatric urological, cytogenetic and endocrinological investigations and the diagnostic procedures are described and discussed. A prevention protocol for patients with comparable gonosomal mosaicism is presented.

Child, Preschool↗