Recurrent adjacent-2 segregation of a familial t(14;21)(q11.2;q11.2): phenotypic comparison of two brothers and a paternal aunt inheriting the der(14).

A 14-year-old boy was referred for a genetics evaluation after high-resolution chromosome analysis showed a small amount of extra material in the proximal long arm of chromosome 21. Five years prior, his karyotype analysis was interpreted as normal with a variant chromosome 21. The patient has short palpebral fissures, strabismus, flat antihelices of the ears, long thumbs with bilaterally absent interphalangeal creases, proximal bilateral 3/4 syndactyly, small testes, hypotonia, mental retardation, and speech problems.

Location of the retinoblastoma susceptibility gene(s) and the human esterase D locus.

Retinoblastoma occurs with increased frequency in children born with a deletion of the long arm of chromosome 13. Recent reviews have noted that the region 13q14 is consistently deleted in documented cases. Prometaphase and late prophase banding allowed Yunis and Ramsay to determine that a deletion in one patient included the sub-bands q14 .

Deletions of different segments of the long arm of chromosome 4.

We report the clinical and chromosomal findings in 8 patients with deletions of the long arm of chromosome 4. Four of these patients appear to have terminal deletions beginning in band 4q31, and therefore, lack the digital 1/3 of the long arm of chromosome 4. We confirm that deletion of 4q31 leads to qter causes a recognizable syndrome, and we further define the phenotype of that syndrome.

GENFILES: a computerized medical genetics information network. III. Chromo: the cytogenetics database.

The computer database CHROMO is the cytogenetic branch of the GENFILES medical genetics information system. Complete cytogenetic laboratory data are maintained in a format that allows detailed searches of client records. Both the standard and extended Paris nomenclature are used.

GENFILES: a computerized medical genetics information network. II. MEDGEN: the clinical genetics system.

MEDGEN, a clinical genetics information storage and retrieval system, facilitates the handling of medical records for the central genetics clinic and satellite clinics conducted by the University of California, San Francisco. The system is part of the GENFILES genetics network, which handles all of the genetics data generated by a comprehensive medical genetics center. The clinical data stored on each patient include 1) diagnoses, which utilize McKusick catalog numbers as well as our own diagnostic codes; 2) relevant medical, gestational, and pregnancy history; 3) clinical manifestations (functional and structural); 4) karyotype information through a crosslink to the cytogenetics file; 5) ethnic origin of the patients; 6) physical status and sex of the patient; 7) laboratory studies, including results of metabolic tests; and 8) any additional remarks deemed necessary for complete understanding.

GENFILES: a computerized medical genetics information network. I. An overview.

GENFILES is a comprehensive computer information network to serve research, service, and administrative needs in medical genetics. Four major databases contain detailed information generated by the cytogenetics laboratory, the prenatal diagnosis program, the diagnostic and genetic counseling clinics, and the human cell culture facility. Unique aspects are the use of RAMIS, a commercial database management system, and of microprocessor computers as "intelligent" terminals with significant data-handling capabilities.

Visible light observations on the kinetochore of the Indian muntjac, Muntiacus muntjac, Z.

We report here a silver stain technique (Kt stain) for locating the kinetochore (centromere body) without concomitant staining of C-band material. We compare our observations with those obtained from C-banding, Cd (centromeric dot) banding, and electron micrographs, and we report preliminary observations on Indian muntjac centromeres.

Partial trisomy for the distal long arm of chromosome 5 (region q34 leads to qter). A new clinically recognizable syndrome.

This report describes a family in which eight individuals in three generations had mental retardation in association with a characteristic pattern of clinical problems and physical abnormalities including short stature, eczema, hernias, delayed puberty, dysmorphic facies and digital anomalies. The family history was consistent with a chromosomal rearrangement with transmission through balanced carriers. Routine ASG banding studies showed extra chromosomal material on a chromosome 16 but failed to demonstrate any differences between the affected individuals and the presumed carriers.

Prenatal genetic diagnosis in 3000 amniocenteses.

We analyzed 3000 consecutive amniocenteses for prenatal diagnosis to assess the frequency of abnormalities, safety of the procedure, technical and interpretive difficulties and overall diagnostic accuracy. Chromosomal abnormalities were detected in 2.4 per cent of the 2404 pregnancies tested because of advanced maternal age (greater than or equal to 35 years), in 1.

LSD and genetic damage.

Of nine studies in vitro, six have indicated some degree of induced chromosomal breakage after exposure to LSD; three failed to confirm these results. The damage, when found, was generally of the chromatid type, arising during or after DNA synthesis. This damage, with one exception, was the result of concentrations of drug and durations of exposure which could not be achieved in humans with reasonable dosages.

Leukocytes of humans exposed to lysergic acid diethylamide: lack of chromosomal damage.

Leukocyte cultures from eight human subjects who had had recent exposure to large doses of lysergic acid diethylamide were examined for chromosome abnormalities. The number of abnormalities was not significantly greater than that in control cultures.