Ring chromosome

About: Ring chromosome is a research topic. Over the lifetime, 1546 publications have been published within this topic receiving 31061 citations. The topic is also known as: supernumerary circular chromosome.

Ring chromosome 11 [46,XX,r(11) (p15q25)] associated with clinical features of the 11q- syndrome.

Abstract: A 2-year-old girl with a ring of chromosome 11[46,XX,r(11)(p15q25)] was reported. Her clinical features included growth and psychomotor retardation, microbrachycephaly, hypertelorism, strabismus externus, short nose, low nasal bridge, low-set ears, microretrognathism, short neck, small opening of vagina with large clitoris, deformity of nails, cafe-au-lait spot of the skin, general hirsutism, congenital heart disease, generalized convulsions, and pancytopenia. Most of these features are those characteristic of the 11q- syndrome. The fact that the patients with the deletion distal from q22 (reported cases) to q25 (our case) had a common phenotype suggests that the loss of the q25 leads to qter segment is mainly responsible for the characteristic clinical features of the 11q- syndrome.

Ring chromosome 2: clinical, chromosomal, and biochemical aspects.

Abstract: A new case of ring chromosome 2 is described and compared with the five cases hitherto reported. The clinical picture includes a severe pre- and postnatal growth failure, microcephaly, psychomotor retardation, and some minor dysmorphic features. Cytogenetic studies revealed a ring 2 structure and aneuploidy. Banding analysis failed to demonstrate a substantial loss of chromosomal material. Enzymologic studies revealed a decrease of red cell acid phosphatase activity suggesting the localization of its gene in the 2p25→2pter region.

Ring 14 chromosome presenting as early‐onset isolated partial epilepsy

Abstract: We report four infants (two males, two females) with ring 14 chromosome presenting with early-onset partial epilepsy. The first seizure occurred between 3 and 6 months (3, 3, 4, and 6mo respectively). In all four cases, diagnosis was based on early focal seizures, rather than on psychomotor retardation or morphological features, which were not prominent at seizure onset. Moreover, despite the young age of the patients and the high frequency of seizures, neither epileptic spasms nor progression to 'epileptic encephalopathy', such as hypsarrhythmia, were observed. Epilepsy remained partial in these patients. At the most recent follow-up, all four children had slight or mild psychomotor delay, and two of them had moderate non-specific dysmorphic traits. Data from the literature about epilepsy in ring 14 chromosome syndrome were also reviewed. Ring 14 chromosome syndrome may be revealed by isolated, early-onset focal epilepsy suggestive of focal lesions with only mild mental retardation and morphological features at the time of diagnosis. The characteristics of these observations differ from classic ring 14 syndrome, and may enlarge this clinical spectrum. Many unanswered questions remain concerning phenotype-genotype correlation and identification of the potential genes and molecular mechanisms responsible for epilepsy in patients with ring 14 syndrome.