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.