Ring chromosome 7 and sacral agenesis

Abstract

A ring chromosome 7 was found in a 19-month-old girl with microcephaly, growth and developmental delay, multiple angiomas, and partial sacral agenesis. Absent sacrum is a frequent finding in patients with 7q terminal deletions; in fact, genes involved in the sacral agenesis are localized in 7q36. However, this anomaly was not described previously in patients with a ring chromosome 7. High resolution G-banding chromosome and fluorescence in situ hybridization (FISH) demonstrated that our patient lost this region during ring formation.

De novo supernumerary ring chromosome 7: first report of a non‐mosaic patient and review of the literature

“…One of the most significant features present in almost all the cases with a large ring chromosome (group 2) is the presence of skin lesions. Out of the 14 cases with large ring chromosomes, 13 showed skin lesions such as vascular lesions (hemangiomas) café‐au‐lait spots and pigmented nevi (1–12, 14). Such strong association between the presence of a large ring chromosome 7 and skin lesions has led some investigators to propose a possible link between ring chromosome and malignant melanoma (17).…”

“…and in the present subject. With the exception of three patients with large ring chromosomes 7 (1, 7, 14), none of the other patients had speech difficulties reported, although most of the patients with large ring chromosomes 7 were diagnosed very early in infancy, and as such, no information was available about the speech impairment in these patients. Another significant feature reported by Tan‐Sindhunata et al.…”

Ring syndrome caused by ring chromosome 7 without loss of subtelomeric sequences

“…In all instances, the total length of the ring chromosome 7 was approximately equal to the normal chromosome 7, cytogenetically suggesting deletions of the terminal regions of the chromosome arms. All cases were mosaic (1).…”

Williams-Beuren syndrome associated with caudal regression syndrome and coagulopathy—a case report

“…Dias and Walker suspect a faulty gastrulation in the form of an abnormal development of the notocord to be the main cause of CRS [12]. In several patients, a terminal deletion of the long arm of chromosome 7 (q36-qter) that produces a haploinsufficiency of the HLXB9 gene has been reported to be associated with sacral agenesis [13,14]. In the Currarino triad (imperforate anus or anal stenosis, genitourinary malformations, and sacral cleft with anterior meningocele or teratoma), heterozygous point mutations in HLXB9 have been described, but not in the clear CRS [15,16].…”