Jacobsen Syndrome, also known as 11q deletion disorder, is a rare congenital disorder resulting from deletion of a terminal region of chromosome 11 that includes band 11q24.1. It can cause intellectual disabilities, a distinctive facial appearance, and a variety of physical problems including heart defects and a bleeding disorder. The syndrome was first identified by Danish physician Petra Jacobsen, and is believed to occur in approximately 1 out of every 100,000 births.
Signs and symptoms
Characteristics may include
- Heart defects
- Mild to severe intellectual disabilities
- Low-platelets (thrombocytopenia)
- Facial/skeletal (dysplasia)
- Wide-set eyes caused by trigonocephaly
- Folding of the skin near the eye (epicanthus)
- Short, upturned nose (anteverted nostrils)
- Thin lips that curve inward
- Displaced receding chin (retrognathia)
- Low-set, misshapen ears
- Permanent upward curvature of the pinkie and ring fingers (camptodactyly)
- Large great toes/Hammer toes
In addition, people tend to be shorter than average and have poor psychomotor skills.
The majority of Jacobsen syndrome cases are not familial in nature, resulting from a spontaneous mutation occurring in a single parental gamete. However, some instances of familial disease resulting from local chromosome fragility or an unbalanced translocation have been described.
One study also found less than half of the participants with Jacobsen syndrome were also diagnosed with an autism spectrum disorder.
- Jacobsen P, Hauge M, Henningsen K, Hobolth N, Mikkelsen M, Philip J (1973). “An (11;21) translocation in four generations with chromosome 11 abnormalities in the offspring. A clinical, cytogenetical, and gene marker study”. Hum. Hered. 23 (6): 568–85. doi:10.1159/000152624. PMID 4134631.
- Grossfeld PD, Mattina T, Lai Z, Favier R, Jones KL, Cotter F, Jones C. 2004. The 11q terminal deletion disorder: A prospective study of 110 cases. Am J Med Genet 129A: 51-61.
- Akshoomoff N, Mattson S, Grossfeld PD. 2015. Evidence for autism spectrum disorder in Jacobsen syndrome: Identification of a candidate gene in distal 11q. Genetics in Medicine, 17, 143–148.