Clinical and genetic characteristics of mucopolysaccharidosis type VI according to the Russian registry

Table 1 Demographic and clinical characteristics of patients with mucopolysaccharidosis type VI

Parameter	n	Results (n = 53), n (%) or median (Q1; Q3)/ minimum and maximum
Sex, female/male, n (%)	27/26	27/53 (50.9)/27/53 (49.1)
Current age of the patient, years	53	19.0 (12.0; 30.0)/1.0-52.0
Age of first symptoms, years	38	2 (1.0; 4.0)/0.0-20.0
Age of molecular genetic diagnostics, years	40	11 (5/0; 19.0)/0.0-45
Age at diagnosis, years	44	7 (3.0; 14.0)/0.0-41
Time since first symptoms to genetic confirmation, years	34	7 (2.0; 15.0)/0.0-36
Ever received ERT, n (%)	48	48/51 (94.1)
Time since first symptoms of ERT, years	25	7 (4.0; 14.0)/0.0-36
Time since diagnosis to ERT, years	27	2 (0.0; 10.0)/0.0-21
Alive/died, n (%)	53	51 (96.2)/2 (3.8)
Age of death, years	1	25

ERT: Enzyme replacement therapy; Q1-Q3: Quartiles.

Table 2 Prevalence of mucopolysaccharidosis type VI in the federal districts of the Russian federation

Federal district	Number of patients with MPS VI, n (%)	Number of residents in the federal district	Prevalence of MPS VI in the federal district per 100000 live births
Central	10 (18.9)	40198659	0.03
Southern	3 (5.7)	16624081	0.02
Northwestern	7 (13.2)	13840352	0.05
Privolzhsky	6 (11.3)	28540832	0.02
Far-Eastern	2 (3.8)	7866344	0.03
North-Caucasian	9 (16.9)	10251083	0.09
Ural	10 (18.9)	12262295	0.08
Siberian	6 (11.3)	16567143	0.04

MPS VI: Mucopolysaccharidosis type VI.

Table 3 Distribution and genetic variants frequency in patients with mucopolysaccharidosis type VI, n (%)

Single nucleotide variant	Number of patients with a specific variant, n = 51
с.1601А>G (p.Ter534Trp)	2 (3.9)
c.691-1G>A	1 (2.0)
c.454C>T (p.Arg152Trp)	22 (43.1)
c.966G>A (p.Trp322*)	5 (9.8)
c.194C>T (p.Ser65Phe)	10 (19.6)
c.304C>G (p.Arg102Gly)	1 (2.0)
c.797A>C (p.Tyr266Ser)	2 (3.9)
c.974G>A (p.Gly325Asp)	1 (2.0)
c.943C>T (p.Arg315*)	5 (9.8)
c.237_243delGGTGCTC (p.Val80Trpfs*32)	1 (2.0)
c.629A>G (p.Tyr210Cys)	4 (7.8)
c.1562G>A (p.Cys521Tyr)	2 (3.9)
c.533A>G (p.His178Arg)	2 (3.9)
c.262C>T (p.Gln88*)	3 (5.9)
c.1079T>C (p.Leu360Pro)	1 (2.0)
c.743delC (p.Pro248fs)	1 (2.0)
c.785dupA (p.Asn262fs)	1 (2.0)
c.293T>C (p.Leu98Pro)	2 (3.9)
c.1131G>T (p.Trp377Cys)	1 (2.0)
c.941T>C (р.Leu314Pro)	3 (5.9)
ex5: Del2635kb	1 (2.0)
с.990_1003del14	1 (2.0)

Table 4 Prevalence of mucopolysaccharidosis type VI in the Russian Federation in comparison with data from other countries

Country	Selective screening period (years)	Number of identified patients with MPS	MPS incidence per 100000 live births	Number of identified patients with MPS VI	MPS VI incidence per 100000 live births
Russia[16]	31	467	3.9	68	0.036
United States of America[20]	20	789	0.98	-	0.04
Japan[25]	27	467	1.53	8	0.03
Denmark[18]	30	33	1.77	1	0.05
Czech Republic[26]	34	119	3.72	2	0.05
Poland[21]	40	392	1.8	4	0.013
Switzerland[25]	34	51	1.56	4	0.11
Saudi Arabia[23]	26	28	17.0	13.0	7.85
Taiwan[27]	21	130	2.04	9	0.14
South Korea[28]	19	147	1.35	2	0.019
Australia[29]	17	188	4.46	19	0.43
Germany[19]	16	474	3.51	33	0.23

MPS VI: Mucopolysaccharidosis type VI; MPS: Mucopolysaccharidosis.