China
Africa
Explore chapters and articles related to this topic
Microdeletion Syndromes
Published in Merlin G. Butler, F. John Meaney, Genetics of Developmental Disabilities, 2019
Gopalrao V. N. Velagaleti, Nancy J. Carpenter
Jacobsen syndrome is caused by a deletion on the long arm of chromosome 11 extending from q23 to the terminus. More than 85% of the deletions are terminal in nature, whereas the remainder are interstitial deletions. The majority of the deletions are de novo in origin, with a few cases resulting from familial balanced translocations and ring chromosomes (52). Fryns et al. (58) suggested that the deletion of sub-band 11q24.1 is crucial for the full expression of the phenotype. Unlike some of the other microdeletion syndromes, no parent-of-origin effect has been shown for the deleted chromosome 11 in Jacobsen syndrome. Interestingly, deletion break points that are proximal seem to have a bias towards the maternally derived chromosome 11, whereas those that are distal are often paternally derived (53). However, there appears to be no clinical significance as yet associated with this bias. Recent studies have shown that the break points in Jacobsen syndrome patients cluster within CCG-trinucleotide repeats, thus indicating a common mechanism for the chromosome breakage in this region of chromosome 11, leading to Jacobsen syndrome (59).
Hypoplastic left heart syndrome (HLHS): molecular pathogenesis and emerging drug targets for cardiac repair and regeneration
Published in Expert Opinion on Therapeutic Targets, 2021
Anthony T Bejjani, Neil Wary, Mingxia Gu
In addition to single-gene mutation, chromosomal deletions have also been shown to cause CHDs. In particular, patients with Jacobsen syndrome, a chromosomal disorder characterized by the deletion of the distal end of chromosome 11q, often develop serious CHDs, 5–10% of which are HLHS [30]. Ye et al. showed that deleting ETS-1, a gene found in the distal end of chromosome 11, leads to the development of ventricular septal defects and a non-apex forming LV, a characteristic of HLHS hearts [30]. This not only highlights the role of ETS-1 in proper cardiogenesis but also shows that HLHS is a more complex defect that is the result of several contributing factors. Table 1 summarizes some of the genes/chromosomal disorders that have been associated with HLHS directly, or a CHD commonly present in HLHS hearts.
Familial exudative vitreoretinopathy (FEVR) in a child with novel microarray-defined deletion of 11q14 previously diagnosed as retinopathy of prematurity (ROP)
Published in Ophthalmic Genetics, 2023
Ashley López-Cañizares, Thomas A. Lazzarini, Carlos Mendoza, Audina M. Berrocal
During the initial neonatal evaluation, a microarray genetic analysis had been performed that revealed two interstitial deletions on chromosomes 2q and 11q. Larger deletions of 11q have been correlated with microcephaly, developmental delay, craniofacial anomalies, short stature, low set ears, and hypertelorism. Involvement of 11q24.1 is the critical deletion required for the Jacobsen syndrome phenotype. In our patient, this region of 11q did not overlap with the distal region associated with Jacobsen syndrome (13). Larger deletions of 2q32 region are associated with 2q32.2q33 deletion syndrome (14). However, the deletion in our patient did not contain the genes (notably SATB2 (15)) thought to define the critical region for this phenotype.