NOVEL MUTATION IN THE COL11A1 GENE CAUSING
MARSHALL-STICKLER SYNDROME IN THREE
GENERATIONS OF A BULGARIAN FAMILY
Mladenova M1,2,*, Todorov T2, Grozdanova L3, Mitev V1, Todorova A1,2
*Corresponding Author: Dr. Mihaela Mladenova, Department of Medical Chemistry and Biochemistry,
Medical University Sofia, 15 Acad. Ivan Geshov Str. Sofia, Bulgaria. Tel.: +359-9520-522. Fax:
+359-2-9155-049. E-mail: mihaela.mladenova@gmail.com
page: 95
|
|
METHODS
Informed consent was obtained from the patient’s
father prior to genetic testing. The study was approved
by the Ethics Committee of Sofia Medical University,
Sofia, Bulgaria.
Molecular Genetic Methods. Genomic DNA was
extracted from blood leukocytes. Polymerase chain reac tion (PCR) and Sanger sequencing were performed in
order to screen for germline mutations in the COL2A1 and
COL11A1 genes. All coding exons and exon-intron boundaries
of the primers were designed to specifically amplify.
The electrophoretic separation was performed on ABI
PRISM® 3130 Genetic Analyzer (Applied Biosystems,
Foster City, CA, USA). The sequencing reaction was performed
by BigDye®Terminator cycle sequencing kit v.3.1
(Applied Biosystems) that includes Thermo Sequenase II
DNA polymerase and fluorescently labeled nucleotides.
The sequencing profiles were interpreted by the software
Sequencing Analysis v5.1.1 (https://assets.thermofisher.
com/TFS-Assets/LSG/manuals/cms_041266.pdf). The
mRNA reference sequence was based on the information
available from Human COL 11A1, RefSeq NM_001854,
accession number NM_001854 (https://www.ncbi.nlm.
nih.gov/nuccore/1519243093). Human COL2A1, RefSeq
NM_001844, accession number NM_001844 (https://
www.ncbi.nlm.nih.gov/nuccore/1519243785).
Results and Discussion. Based on the higher percentage
of mutations in the COL2A1 gene, we analyzed this
gene as the first target in our family. The COL2A1 gene
tested negative in the family and we further sequenced
the COL11A1 gene. A novel splicå-site mutation c.3474+1
G>A was found at intron 44 (Human COL11A1, RefSeq
NM_001854). The segregation analysis in the family
showed that the father is a carrier of the above mentioned
variant, c.3474+1G>A, which is related to the clinical
presentation of both the proband and her father.
The mutation c.3474+1G>A at intron 44 affects the
donor splice-site, and as a result of altered splicing, gives a
nonfunctional protein. The variant is localized in the region
encoding the major triple-helical domain that represents a
hot-spot for mutations on the COL11A1 gene [12].
In the present genetic variant, the purine nucleotide
guanine (G) is substituted by the purine nucleotide
adenine (A), an event known as transition. We analyzed
the neighboring sequence of 22 bp upstream and 22 bp
downstream of the mutation. The surrounding area is
abundant with repeated elements (AA, GG and TT) and
trinucleotide palindromic sequence AAA/TTT, closely
situated to the position of the substitution (Figure 4).
The repeated and palindromic sequences might play a
role in a G>A substitution and the transition fixation in
the genome. The DNA polymerase proof-reading activity
at this position might be impaired by a secondary structure
formation, making chemically identical substitutions
difficult to recognize and remove, thus leading to their
fixation in the genome.
In conclusion, the present report concerns the first
familial case spread through at least three generations,
genetically verified case of Marshall-Stickler syndrome
in Bulgaria, caused by a novel splice-site mutation in the
triple-helical domain of the COL11A1 gene.
Acknowledgments. The study was partially supported
by the Medical University Sofia [Grant No.
D-117/2018].
Declaration of Interest. The authors report no conflicts
of interest. The authors alone are responsible for the
content and writing of this article.
|
|
|
|
 |
Number 27
VOL. 27 (2), 2024 |
Number 27
VOL. 27 (1), 2024 |
Number 26
Number 26 VOL. 26(2), 2023 All in one |
Number 26
VOL. 26(2), 2023 |
Number 26
VOL. 26, 2023 Supplement |
Number 26
VOL. 26(1), 2023 |
Number 25
VOL. 25(2), 2022 |
Number 25
VOL. 25 (1), 2022 |
Number 24
VOL. 24(2), 2021 |
Number 24
VOL. 24(1), 2021 |
Number 23
VOL. 23(2), 2020 |
Number 22
VOL. 22(2), 2019 |
Number 22
VOL. 22(1), 2019 |
Number 22
VOL. 22, 2019 Supplement |
Number 21
VOL. 21(2), 2018 |
Number 21
VOL. 21 (1), 2018 |
Number 21
VOL. 21, 2018 Supplement |
Number 20
VOL. 20 (2), 2017 |
Number 20
VOL. 20 (1), 2017 |
Number 19
VOL. 19 (2), 2016 |
Number 19
VOL. 19 (1), 2016 |
Number 18
VOL. 18 (2), 2015 |
Number 18
VOL. 18 (1), 2015 |
Number 17
VOL. 17 (2), 2014 |
Number 17
VOL. 17 (1), 2014 |
Number 16
VOL. 16 (2), 2013 |
Number 16
VOL. 16 (1), 2013 |
Number 15
VOL. 15 (2), 2012 |
Number 15
VOL. 15, 2012 Supplement |
Number 15
Vol. 15 (1), 2012 |
Number 14
14 - Vol. 14 (2), 2011 |
Number 14
The 9th Balkan Congress of Medical Genetics |
Number 14
14 - Vol. 14 (1), 2011 |
Number 13
Vol. 13 (2), 2010 |
Number 13
Vol.13 (1), 2010 |
Number 12
Vol.12 (2), 2009 |
Number 12
Vol.12 (1), 2009 |
Number 11
Vol.11 (2),2008 |
Number 11
Vol.11 (1),2008 |
Number 10
Vol.10 (2), 2007 |
Number 10
10 (1),2007 |
Number 9
1&2, 2006 |
Number 9
3&4, 2006 |
Number 8
1&2, 2005 |
Number 8
3&4, 2004 |
Number 7
1&2, 2004 |
Number 6
3&4, 2003 |
Number 6
1&2, 2003 |
Number 5
3&4, 2002 |
Number 5
1&2, 2002 |
Number 4
Vol.3 (4), 2000 |
Number 4
Vol.2 (4), 1999 |
Number 4
Vol.1 (4), 1998 |
Number 4
3&4, 2001 |
Number 4
1&2, 2001 |
Number 3
Vol.3 (3), 2000 |
Number 3
Vol.2 (3), 1999 |
Number 3
Vol.1 (3), 1998 |
Number 2
Vol.3(2), 2000 |
Number 2
Vol.1 (2), 1998 |
Number 2
Vol.2 (2), 1999 |
Number 1
Vol.3 (1), 2000 |
Number 1
Vol.2 (1), 1999 |
Number 1
Vol.1 (1), 1998 |
|
|
