Table 1.
Case 1 |
Case 2 |
Case 3 |
Case 4 |
|
---|---|---|---|---|
MPS I? | Pompe? | Gaucher? | MPS I? | |
Enzyme analysis | IDUA |
GAA |
GBA |
IDUA |
DBS-fluorometry | Undetectable | NP | 2.8 nmol/h/mL | NP |
(2.2–17) | ||||
Plasma-fluorometry | 11 nmol/h/mL | NP | NP | NP |
(6.6–34) | ||||
Leukocytes-fluorometry | 11 nmol/h/mg protein | 1.00 nmol/h/mg protein | 5.6 nmol/h/mg protein | 27 nmol/h/mg protein |
(27–171) | (1.00–7.60) | (10–45) | (27–171) | |
Father: 1.9 | Father: 8.1 | |||
Mother: 2.70 | Mother: 22.0 | |||
Urinary GAGs | ||||
Quantitation (DMB - colorimetry) | 197 μg/mg creatinine | NP | NP | 272 μg/mg creatinine |
(133–460) | (133–460) | |||
Electrophoresis (qualitative) | Normal GAG pattern | NP | NP | Normal GAG pattern |
Gene analysis |
IDUA |
GAA |
GBA |
IDUA |
Mutation 1 | c.251G>C | c.-32-13T>G | c.1226A>G | c.1205G>A |
Effect | p.(Gly84Ala) | Splice site variant | p.Asn409Ser (N370S) | p.Trp402Ter |
Significance | Predicted pathogenic | Pathogenic variant | Pathogenic variant | Pathogenic variant |
Mutation 2 | c.246C>G | c.[1726G>A; 2065G>A] | No pathogenic variant identified | No pathogenic variant identified |
Effect | p.His82Gln | p.[Gly576Ser; Glu689Lys] | ||
Significance | Pseudodeficiency allele | Pseudodeficiency allele | ||
Father: c.-32-13T>G | Father: c.1205G>A | |||
Mother: p.[Gly576Ser; Glu689Lys] | Mother: No pathogenic variant |
Numbers in parenthesis, in enzyme analysis and urinary GAGs, are reference values. IDUA: α-L iduronidase; GAA: acid α-glucosidase; GBA: acid β-glucosidase; MPS I: mucopolysaccharidosis type 1. DBS: dried blood spot; GAGs: glycosaminoglycans. NP: not performed.