Cytogenetic forms of retinoblastoma: their incidence in a survey of 66 patients.

Sixty-six retinoblastoma patients were investigated using high resolution banding techniques, sister chromatid exchange (SCE) studies, and esterase-D phenotype determination and dosage. Seven patients (in six families) were found to be carriers of a rearrangement of band 13q14 due to de novo deletions, apparently balanced de novo translocations, or parental insertions. The possible role of submicroscopic parental insertions is suggested to explain transmission of nonchromosomal forms through unaffected carriers.

Trisomy 11p15 and Beckwith-Wiedemann syndrome. A report of two cases.

Two patients with trisomy 11p15 and features of Beckwith-Wiedemann syndrome are reported. The first is a female infant with gigantism, macroglossia, abdominal hypotonia with umbilical hernia, moderate mental retardation, malformative uropathy, and atrial septal defect. Trisomy 11p15 was due to de novo duplication.

Regional mapping of clotting factors VII and X to 13q34. Expression of factor VII through chromosome 8.

Blood clotting factors were investigated in a patient with trisomy 8 mosaicism, a patient with an r(13), and a patient with distal trisomy 13q. Results are compatible with the assignment of the structural genes of factors VII and X to 13q34 and the existence of a regulatory mechanism associated with chromosome 8 controlling the expression of factor VII alone.

Two patients with interstitial del (14q), one with features of Holt-Oram syndrome. Exclusion mapping of PI (alpha-1-antitrypsin).

Patient no 1, a boy, was carrier of a de novo del (14) (pter- greater than q23::q32- greater than qter). Patient no 2, a boy, had a de novo del (14) (pter- greater than q23::q24.2- greater than qter).

Del11p13/nephroblastoma without aniridia.

A patient is reported with del11p13, low catalase level, nephroblastoma, chordee and cryptorchidism, no evident mental retardation, and with normal irides. This unique observation suggests the following order of loci in 11p13, from centromere to telomere: catalase, Wilms tumor, aniridia. The chromosomal origin of nephroblastoma may be more frequent than estimated on the basis of its association with aniridia.