Table 1 Clinical biochemical and molecular features of MPSIVA patients

Phenotype

severe

mild

severe

Age

14 y 6 m

16y

14y

Age at diagnosis

3y 5 m

8y

3y

Age at onset

3 m

3y

2-3y

GALNS activity (nmol/17 h/mg protein)

0.07 (nv 40–170)

0.2 (nv 40–170)

0 (nv 70–180)

Genotype

c.463G > A (ex 5)/ c.899-167A > G

c.463 G > A (ex 5)/ c.1002 + 307G > C^

c.697G > A (ex 7)/ c.759-67G > A^

mRNA alteration

−/ r.898_899ins53

−/ r.1003_1119del

−/ r.456_916del

Protein alteration

p.Gly155Arg / p.Gly300Valfs*37

p.Gly155Arg/ p.(Val335_Leu373del)

p.Asp233Asn/ p.(Lys153_Phe306del)

Sex

female

female

male

Parental consanguinity

no

no

no

Height (cm) at diagnosis

89.5

121

–

Height (cm) at last observation

108.6

136.3

114.5

Weight (kg)

18.2

26.6

27.5

Spondyloepiphyseal dysplasia

yes

yes

yes

Chest deformity

yes

yes

yes

Hearing loss

–

no

yes

Corneal clouding

no

mild

no

Coxa valga

yes

yes

yes

Odontoid hypoplasia

yes

yes

no

Hepatomegaly

no

yes

mild

Cardiomyopathy

yes

no

no

Valvular regurgitation

–

no

mitral/ tricuspid

Mental retardation

no

no

WISC-III TIQ 89

Surgery (type and age)

odontoid hypoplasia (7y), coxa valga (13y), cardiomyopathy (9 m)

right hip (6y), left hip (7y), coxa valga (10y)

coxa valga (10y)

Urine GAGs (mg/g creatinine)

92 (nv 48–82)

52 (nv 10–63)

6.6 (nv 2.1–23.2)