A small autosomal ring chromosome in a female infant with congenital malformations

Abstract

SUMMARY A mentally retarded child with congenital malformations is described in whom a high proportion of cells contained a small ring chromosome derived from a no. 18 (Denver classification). The variability in the morphological appearance of the ring chromosome is illustrated and its stability is discussed in relation to other instances of ring chromosomes in both man and other organisms. The writers wish to thank Dr Margaret D. Baber and Dr Ursula James for their co‐operation during this investigation, Mr A. J. Lee for preparing the figures and Miss Penelope M. Carr, Miss Linda Z. Gorman and Miss Barbara J. Warland for technical assistance. Research grants from the British Empire Cancer Campaign (N.H.K.), from St George's Hospital (M.K.L.) and from the United States Public Health Service (RG‐6984) (J.R.E. and R.M.) made this study possible.

Ring chromosome 18 in a patient with multiple anomalies.

“…All patients bearing the ring 18 are characterized by mental retardation. The one reported by Lucas, Kemp, Ellis, and Marshall (1963) and our patient have the common finding of microcephaly. A number of ring-chromosome bearing subjects have abnormalities in the formation of the ears, atresia of the middle ear (Wang, Melnyk, McDonald, Uchida, Carr, and Goldberg, 1962;Gropp, Jussen, and Ofteringer, 1964), and low-set ears.…”

Anopthalmia and Other Anomalies Associated with a Ring Chromosome No. 17-18

“…The phenotypes of the twenty-four known cases with a ring chromosome 17 or 18 have been reported. (Wang et al 1962, Genest et al 1963, Lucas et al 1963, Gropp et al 1964, de Grou chy et al 1965, Bernard et al 1966, Lejeune et al 1966, Aula et al 1967, Mikelsaar et al 1967, Palmer et al 1967, Petit and Poncelet 1967, de Grouchy et al 1968, Hooft et al 1968, Leist et al 1968, Sinha 1968, Richards et al 1968, Cenani et al 1969, Ricci et al 1969, Dumars et al 1970, Christensen et al 1970a. b., Chang et al 1973.…”

A case of 46,XX,18p–/46,XX,r(18) mosaicism

“…Some of the r(18) cases were accompanied with cells involving a loss of one of No. 18 chromosomes, i.e., a mosaicism of 46,XX,r(18)/45,XX,-18 (Lucas et al, 1963;Gripenberg, 1967). Similar instances of mosaicism with structural abnormalities in one of No.…”

“…18, for example, a partial deletion of the short arm, 18p-(de Grouchy et aI., 1963;Summitt, 1964;Van Dyke et aI., 1964) or the long arm, 18q-(de Grouchy et al, 1964;Law and Masterson, 1966;Lejeune et al, 1966), and a ring chromosome, r(18) (Wang et al, 1962;Lucas et al, 1963;Gropp et aI., 1964), have been reported. Some of the r(18) cases were accompanied with cells involving a loss of one of No.…”