TY - JOUR
T1 - Detection of variants in SLC6A8 and functional analysis of unclassified missense variants
AU - Betsalel, Ofir T.
AU - Pop, Ana
AU - Rosenberg, Efraim H.
AU - Fernandez-Ojeda, Matilde
AU - Jakobs, Cornelis
AU - Creatine Transporter Research Group
AU - Frints, Suzanne
AU - Salomons, Gajja S.
PY - 2012/4
Y1 - 2012/4
N2 - Creatine transporter deficiency is an X-linked disorder caused by mutations in the SLC6A8 gene. Currently, 38 pathogenic, including 15 missense variants, are reported. In this study, we report 33 novel, including 6 missense variants. To classify all known missense variants, we transfected creatine deficient fibroblasts with the SLC6A8 ORF containing one of the unique variants and tested their ability to restore creatine uptake. This resulted in the definitive classification of 2 non-disease associated and 19 pathogenic variants of which 3 have residual activity. Furthermore, we report the development and validation of a novel DHPLC method for the detection of heterozygous SLC6A8 variants. The method was validated by analysis of DNAs that in total contained 67 unique variants of which 66 could be detected. Therefore, this rapid screening method may prove valuable for the analysis of large cohorts of females with mild intellectual disability of unknown etiology, since in this group heterozygous SLC6A8 mutations may be detected. DHPLC proved also to be important for the detection of somatic mosaicism in mothers of patients who have a pathogenic mutation in SLC6A8. All variants reported in the present and previous studies are included in the Leiden Open Source Variant Database (LOVD) of SLC6A8 (www.LOVD.nl/SLC6A8).
AB - Creatine transporter deficiency is an X-linked disorder caused by mutations in the SLC6A8 gene. Currently, 38 pathogenic, including 15 missense variants, are reported. In this study, we report 33 novel, including 6 missense variants. To classify all known missense variants, we transfected creatine deficient fibroblasts with the SLC6A8 ORF containing one of the unique variants and tested their ability to restore creatine uptake. This resulted in the definitive classification of 2 non-disease associated and 19 pathogenic variants of which 3 have residual activity. Furthermore, we report the development and validation of a novel DHPLC method for the detection of heterozygous SLC6A8 variants. The method was validated by analysis of DNAs that in total contained 67 unique variants of which 66 could be detected. Therefore, this rapid screening method may prove valuable for the analysis of large cohorts of females with mild intellectual disability of unknown etiology, since in this group heterozygous SLC6A8 mutations may be detected. DHPLC proved also to be important for the detection of somatic mosaicism in mothers of patients who have a pathogenic mutation in SLC6A8. All variants reported in the present and previous studies are included in the Leiden Open Source Variant Database (LOVD) of SLC6A8 (www.LOVD.nl/SLC6A8).
KW - SLC6A8
KW - Creatine transporter
KW - Missense variants
KW - LOVD
KW - DHPLC
U2 - 10.1016/j.ymgme.2011.12.022
DO - 10.1016/j.ymgme.2011.12.022
M3 - Article
C2 - 22281021
SN - 1096-7192
VL - 105
SP - 596
EP - 601
JO - Molecular Genetics and Metabolism
JF - Molecular Genetics and Metabolism
IS - 4
ER -