Table 1.

Prevalence of clinical manifestations in severe types of MPS II and MPS IH in the absence of therapy.

Manifestation	MPS II (Hunter Syndrome)	References	MPS IH (Hurler Syndrome)	References
Umbilical hernia	70–95%	[12,19]	60–75%	[19,20,21,22]
Inguinal hernia	70–95%	[12,19]	60–75%	[19,20,21,22]
Hepatosplenomegaly	60–90%	[10,12,19,23]	70–85%	[19,20]
Skeletal manifestations	80%	[24]	80%	[22,25]
Kyphosis	34%	[10,12,18,19,23,24]	70–90%	[26]
Odontoid hypoplasia	rare	[10]	65%	[27]
Joint stiffness	75–90%	[10,19,23,24]	93%	[19,20,26]
Poor growth	79%	[12,19,24]	100%	[19,22,24]
Epidermal symptoms (thickened skin with pebble formation, persistent Mongolian spots)	13–17%	[19,28,29,30]	rare
Coarse facial features	95%	[10,23]	86–97%	[13]
Upper respiratory issues	100%	[12,19]	80–100%	[19,20,22,25]
Lower respiratory issues	80–90%	[12,24]	80–90%	[21,22,31]
Loss of hearing	70–95%	[8,12,28,32]	76–100%	[20,25]
Valvular heart disease	50–60%	[10,23,28,33,34]	40–100%	[13,20,21,22,25,35,36]
Corneal clouding	rare	[19]	71–88%	[19,20,21,22,25]
Seizures	60%	[12,37]	rare	[38]
Cognitive impairment	100%	[12,23,28]	100%	[22,39,40]
Behavioral disturbances	30–45%	[8,12,19,23,28,41]	rare	[19]
Diarrhea	60%	[12,19,23,28]	rare	[19]