Chromosome 9 Ring
Incidence
Very rare syndrome. Sporadic. Chromosome 9 Ring usually appears to result from spontaneous (de novo) errors very early in the development of the embryo that occur for unknown reasons (sporadically).
Clinical Characteristics
Chromosome 9 Ring is a rare disorder in which there is loss (deletion) of chromosomal material from both ends of the 9th chromosome and joining of the ends to form a ring. Associated symptoms and findings may vary, depending upon the amount and location of lost chromosomal material and other factors. Some affected individuals may have variable malformations of the skull and facial (craniofacial) region. However, in others with the chromosomal abnormality, such features may not be apparent. Chromosome 9 Ring may also be characterized by additional physical features in some cases, including growth retardation, heart defects, genital abnormalities, and/or other findings. In addition, many affected individuals have moderate to severe mental retardation; however, in some instances, intelligence may be in the low normal range. Chromosome 9 Ring usually appears to result from spontaneous (de novo) errors very early in the development of the embryo that occur for unknown reasons (sporadically).
Precipitants
None
Provocation Tests
None
Diagnostic Procedures
Karyotype. Loss (deletion) of chromosomal material from both ends of the 9th chromosome and joining of the ends to form a ring.