Molecular and functional analysis of SUMF1 mutations in multiple sulfatase deficiency.
Multiple sulfatase deficiency (MSD) is a rare disorder characterized by impaired activity of all known sulfatases. The gene mutated in this disease is SUMF1, which encodes a protein involved in a post-translational modification at the catalytic site of all sulfatases that is necessary for their function. SUMF1 strongly enhances the activity of sulfatases when coexpressed with sulfatase in Cos-7 cells. We performed a mutational analysis of SUMF1 in 20 MSD patients of different ethnic origin. The clinical presentation of these patients was variable, ranging from severe neonatal forms to mild phenotypes showing mild neurological involvement. A total of 22 SUMF1 mutations were identified, including missense, nonsense, microdeletion, and splicing mutations. We expressed all missense mutations in culture to study their ability to enhance the activity of sulfatases. Of the predicted amino acid changes, 11 (p.R349W, p.R224W, p.L20F, p.A348P, p.S155P, p.C218Y, p.N259I, p.A279V, p.R349Q, p.C336R, p.A177P) resulted in severely impaired sulfatase-enhancing activity. Two (p.R345C and p.P266L) showed a high residual activity on some, but not all, of the nine sulfatases tested, suggesting that some SUMF1 mutations may have variable effects on the activity of each sulfatase. This study compares, for the first time, clinical, biochemical, and molecular data in MSD patients. Our results show lack of a direct correlation between the type of molecular defect and the severity of phenotype.
Cosma
Maria Pia
MP
Telethon Institute of Genetics and Medicine, Naples, Italy.
Pepe
Stefano
S
Parenti
Giancarlo
G
Settembre
Carmine
C
Annunziata
Ida
I
Wade-Martins
Richard
R
Di Domenico
Carmela
C
Di Natale
Paola
P
Mankad
Anuj
A
Cox
Barbara
B
Uziel
Graziella
G
Mancini
Grazia M S
GM
Zammarchi
Enrico
E
Donati
Maria Alice
MA
Kleijer
Wim J
WJ
Filocamo
Mirella
M
Carrozzo
Romeo
R
Carella
Massimo
M
Ballabio
Andrea
A
D000818:Animals; D019556:COS Cells; D006801:Humans; D009154:Mutation; D050862:Oxidoreductases Acting on Sulfur Group Donors; D013106:Sphingolipidoses / Q000201:enzymology / Q000235:genetics*; D013429:Sulfatases / Q000172:deficiency / Q000235:genetics*
D050862:Oxidoreductases Acting on Sulfur Group Donors; C480483:SUMF1 protein, human; D013429:Sulfatases