Chromosomal imbalance letter372 kb microdeletion in 18q12.3 causing SETBP1 haploinsufficiency associated with mild mental retardation and expressive speech impairment
Highlights
► SETBP1 haploinsufficiency is related with expressive speech impairment. ► Array-CGH revealed a cryptic microdeletion in an apparently balanced translocation. ► SETBP1 analysis in patients with developmental delay, behavioural problems, verbal dyspraxia.
Section snippets
Cytogenetics
Chromosome analysis was performed according to standard procedures on QFQ-banded metaphase spread from peripheral blood lymphocytes at 350/450-band level. Conventional chromosomal analysis showed the presence of an apparently balanced translocation [46XY, t(2; 18)(q24; q21)]. Parental karyotypes are normal, indicating that the rearrangement originated de novo.
Array-CGH
To further characterize the rearrangement, an oligo array-CGH was performed using the Human Genome CGH 44K Microarray Kit (Agilent
Clinical description
A 5 year old boy was referred to us for speech delay. The patient was the third child of healthy unrelated Caucasian parents with two healthy siblings. Family history revealed maternal grandmother with epilepsy and one maternal cousin with mental retardation. The patient was born after an uneventful term pregnancy. Delivery was normal and birth weight was 3650 g (0 DS), length was 49 cm (0 SDS), and head circumference was 35 cm (0 SD). There was no notion of muscular hypotonia, sucking reflex
Discussion
Proximal interstitial 18q deletions involving cytobands q12 to q21 are described in the literature and define the rare del(18)(q12.2-q21.1) syndrome. The common findings described in patients with proximal interstitial 18q deletions are minor facial anomalies (telecanthus, frontal bossing, deep-set eyes, midface hypoplasia), lack of major congenital defects, hypotonia, mental retardation of variable degree, behavioural disorders (autism spectrum disorder, hyperactivity, aggression), and
Acknowledgements
We would like to thank the patient and his family for their cooperation.
References (13)
- et al.
A 5.3Mb deletion in chromosome 18q12.3 as the smallest region of overlap in two patients with expressive speech delay
Eur. J. Med. Genet.
(2011) - et al.
A shifting level model algorithm that identifies aberrations in array-CGH data
Biostatistics
(2010) - et al.
A very fast and accurate method for calling aberrations in array-CGH data
Biostatistics
(2010) - et al.
Interstitial deletion of the long arm of chromosome 18, del(18)(q12.2q21.1): a report of three cases of an autosomal deletion with a mild phenotype
J. Med. Genet.
(1991) - et al.
Interstitial deletion of the proximal region of the long arm of chromosome 18, del(18q12) a distinct clinical entity? A report of two new cases
Ann. Genet.
(1992) - et al.
Long-term survival in a patient with del(18)(q12.2q21.1)
Am. J. Med. Genet.
(2003)