Ring chromosome 12 with variable phenotypic features: clinical report and review of the literature.
A ring chromosome 12 (p13; q24.33) was observed in all cells analyzed from peripheral blood lymphocytes of a 15-year-old female referred for academic difficulties and growth delay. In addition to clinical manifestations generally observed with ring chromosome 12 such as growth retardation, mental deficiency, microcephaly, the patient had bilateral pseudocamptodactyly of little fingers, mild hirsutism, exaggerated lumbar lordosis, and ostium secundum atrial septal defect (ASD). The clinical features of reported cases are analyzed. The only consistent features were growth retardation and mental deficiency. Breakpoint in all the cases has been at the telomeric region with minimal deletion of chromosomal material. An account of complex changes at mitosis and meiosis in ring chromosome has been given. Examination of 200 metaphases demonstrated 2% cell line was showing 45,XX, -12. Serum lactate dehydrogenase (LDH) level was normal ruling out overlapping monosomy 12 syndrome.
Parmar
Ramesh C
RC
The Genetics Division, Department of Pediatrics, Seth G. S. Medical College and K. E. M. Hospital, Parel, Mumbai 400 055, India. rameshparmar@yahoo.com
Muranjan
Mamta N
MN
Kotvaliwale
S
S
Sharma
Seema
S
Bharucha
B A
BA
D000015:Abnormalities, Multiple / Q000235:genetics / Q000473:pathology; D000293:Adolescent; D001842:Bone and Bones / Q000002:abnormalities; D002871:Chromosome Banding; D025063:Chromosome Disorders / Q000235:genetics / Q000473:pathology; D002881:Chromosomes, Human, Pair 12 / Q000235:genetics*; D002658:Developmental Disabilities / Q000473:pathology; D005260:Female; D005385:Fingers / Q000002:abnormalities; D006130:Growth Disorders / Q000473:pathology; D006344:Heart Septal Defects, Atrial / Q000473:pathology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D010641:Phenotype; D012303:Ring Chromosomes