MOLECULAR MEDICINE REPORTS
Chromosome 10q26 deletion syndrome: Two
new cases and a review of the literature
SHAOBIN LIN*, YI ZHOU*, QUN FANG, JIANZHU WU, ZHIQIANG ZHANG, YUANJUN JI and YANMIN LUO
Fetal Medicine Center, Department of Obstetrics & Gynecology, The First Affiliated Hospital of Sun Yat?Sen University,
Guangzhou, Guangdong 510080, P.R. China
Received September 29, 2015; Accepted October 6, 2016
DOI: 10.3892/mmr.2016.5864
Abstract. The current study presents the cases of two unrelated
patients with similar clinical features, including craniofacial
anomalies, developmental delay/intellectual disability and
cardiac malformations, that are consistent with chromosome
10q26 deletion syndrome. High?resolution single?nucleotide
polymorphism analysis revealed that 10q26 terminal deletions
were present in these two patients. The locations and sizes
of the 10q26 deletions in these two patients were compared
with the locations and sizes of 10q26 deletions in 30 patients
recorded in the DECIPHER database and 18 patients charac?
terized in previous studies through chromosomal microarray
analysis. The clinical features and locations of the 10q26 dele?
tions of these patients were reviewed in an attempt to map or
refine a critical region (CR) for phenotypes. Additionally, the
association between previously suggested CRs and phenotypic
variability was discussed. The current study emphasize that a
distal 10q26 terminal deletion with a breakpoint at ~130 Mb
may contribute to the common clinical features of 10q26 dele?
tion syndrome.
Introduction
The partial deletion of distal chromosome 10q was first
reported by Lewandowski et al (1), and the existence of
a distinct chromosome 10q26 deletion syndrome (Online
Mendelian Inheritance in Man no. 609625) was then suggested
due to consistent clinical findings (2?4). This syndrome
is caused by a rare chromosomal abnormality, although
?110 cases have been reported in the literature. Patients with
Correspondence to: Professor Yanmin Luo, Fetal Medicine
Center, Department of Obstetrics & Gynecology, The First
Affiliated Hospital of Sun Yat?Sen University, 58 Zhongshan
Road II, Guangzhou, Guangdong 510080, P.R. China
E?mail: luoyanm@mail.sysu.edu.cn
*
Contributed equally
Key words: chromosome 10q26 deletion syndrome, critical region,
genotype?phenotype correlation, SNP array
this syndrome present with symptoms that span a relatively
extensive and heterogeneous phenotypic spectrum, although
common clinical features, including craniofacial anomalies,
developmental delay/intellectual disability (DD/ID), urinary
tract abnormalities, cardiac malformations and neurodevelop?
mental deficits, have been observed (4?7). A pure distal 10q
deletion may be derived from familial or de novo structural
variation and feature breakpoints at 10q25 or 10q26, although
interstitial or terminal deletions of large size, which are typi?
cally identified through conventional cytogenetic techniques,
can also occur (4,8). Chromosomal microarray analysis (CMA),
including the use of array comparative genome hybridization
and single?nucleotide polymorphism (SNP) arrays, has been
recommended as the first?tier test for individuals with DD/ID
and/or congenital anomalies (9). CMA has been increasingly
employed to refine the location and size of 10q26 deletions to
improve understanding of genotype?phenotype correlations by
identifying the minimal critical region (CR) or the smallest
region of deletion overlap associated with 10q26 deletion
syndrome. Because this syndrome is a clinically heterogeneous
disorder involving deletions of variable locations and sizes, the
CR for 10q26 deletion syndrome and candidate genes for vari?
able phenotypes remain unclear (10). Therefore, further studies
on patients with 10q26 deletions should be performed to eluci?
date the correlation between various phenotypes and the CR.
The majority of examined cases of this syndrome were previ?
ously characterized using traditional techniques with limited
resolution and low efficiency, including G?banded karyotyping,
fluorescence in situ hybridization and microsatellite marker
genotyping, whereas few CMA?based molecular studies have
been performed to investigate these cases. The current study
attempted to refine a CR for this syndrome by performing a
high?resolution molecular analysis of two unrelated patients
with pure terminal 10q26 deletions and comparing these
patients with patients with pure distal 10q deletions described
in previous CMA?based studies and the Database of Chromo?
somal Imbalance and Phenotype in Humans using Ensembl
Resources (DECIPHER; https://decipher.sanger.ac.uk/),
specifically including patients from this database with deleted
regions encompassed by the deleted regions of the two patients
examined in the current study and that presented without any
other copy number variants or with other likely benign copy
number variants. In addition, the phenotypic variability asso?
ciated with CRs proposed in previous studies is discussed.
2
LIN et al: TWO NOVEL CASES OF 10q26 DELETION SYNDROME
Materials and methods
Case presentation. Patient 1, a 3?year?old female, was the
second child of healthy, unrelated parents. Prenatal ultraso?
nography indicated that duodenal atresia was present in the
fetus; therefore, the karyotyping of fetal blood was performed.
The fetal karyotype did not reveal any chromosomal abnor?
malities (data not shown). Thus, the patient’s parents continued
the pregnancy. Premature rupture of membranes occurred
at 36 weeks of gestation. Eventually, the parents opted for
delivery by caesarian section. No neonatal respiratory distress
was observed. The infant’s weight and length at birth were
2,420 g (
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