Molin A.-M.,Uppsala University |
Andrieux J.,Institute Of Genetique Medicale |
Koolen D.A.,Radboud University Nijmegen |
Malan V.,University of Paris Descartes |
And 30 more authors.
Journal of Medical Genetics | Year: 2012
Background: Congenital deletions affecting 3q11q23 have rarely been reported and only five cases have been molecularly characterised. Genotype-phenotype correlation has been hampered by the variable sizes and breakpoints of the deletions. In this study, 14 novel patients with deletions in 3q11q23 were investigated and compared with 13 previously reported patients. Methods Clinical data were collected from 14 novel patients that had been investigated by high resolution microarray techniques. Molecular investigation and updated clinical information of one cytogenetically previously reported patient were also included. Results: The molecular investigation identified deletions in the region 3q12.3q21.3 with different boundaries and variable sizes. The smallest studied deletion was 580 kb, located in 3q13.31. Genotype?phenotype comparison in 24 patients sharing this shortest region of overlapping deletion revealed several common major characteristics including significant developmental delay, muscular hypotonia, a high arched palate, and recognisable facial features including a short philtrum and protruding lips. Abnormal genitalia were found in the majority of males, several having micropenis. Finally, a postnatal growth pattern above the mean was apparent. The 580 kb deleted region includes five RefSeq genes and two of them are strong candidate genes for the developmental delay: DRD3 and ZBTB20. Conclusion: A newly recognised 3q13.31 microdeletion syndrome is delineated which is of diagnostic and prognostic value. Furthermore, two genes are suggested to be responsible for the main phenotype. Source
Palumbo O.,Laboratorio Of Genetica Medica |
Fischetto R.,Unita Operativa Malattie Metaboliche Genetica Medica |
Palumbo P.,Laboratorio Of Genetica Medica |
Nicastro F.,Unita Operativa Malattie Metaboliche Genetica Medica |
And 3 more authors.
Molecular Cytogenetics | Year: 2015
Background: The CHL1 gene codes for a member of the L1 family of neural cell adhesion molecules. It is highly expressed in the central and peripheral nervous system playing an important role in the building and functioning on the brain. CHL1 proteins are also involved in axonal migration, synaptic formation and plasticity. In mice, functional studies showed that the haploinsufficiency of Chl1 gene in the developing brain results in cognitive deficits suggesting that the CHL1 gene at 3p26.3 is a candidate for an autosomal form of intellectual disability. Furthermore, in humans deletions of CHL1 have been described in patients with neurodevelopmental delay characterized by learning and language difficulties, seizures. Less is known about the potential effect of CHL1 overexpression, and microduplications of CHL1 have been rarely identified. Case presentation: In this report, we describe a male patient with a phenotype characterized by developmental delay, symptoms of hyperactivity, short attention span and speech delay. In addition, minor facial dysmorphic features have been observed. Chromosomal microarray analysis revealed a rare de novo 0.85 Mb microduplication on the short arm (p26.3) of chromosome 3, encompassing a single gene, CHL1. To the best of our knowledge, duplication of chromosome 3p26.3, including only the CHL1 gene, has been described in only one intellectually disabled girl with epilepsy. The duplication described here is the smallest reported so far. In addition, this is the first report describing a patient in which the CHL1 duplication is a de novo event. Conclusions: The clinical and molecular findings reported here are useful to provide further evidence that CHL1 is a dosage sensitive gene suggesting that not only the deletion but also its duplication can cause non-syndromic neurodevelopmental phenotypes. © 2015 Palumbo et al. Source