Arylsulfatase A deficiency (metachromatic leukodystrophy; MLD) |
ARSA
| AR | All MLD features can be found in MSD, incl central & peripheral demyelination & progressive neurologic deterioration | Absence of other systemic findings assoc w/MSD |
Saposin B deficiency (OMIM 249900) |
PSAP
| AR | All saposin B deficiency features can be found in MSD, incl central & peripheral demyelination & progressive neurologic deterioration | Absence of other systemic findings assoc w/MSD |
Mucolipidosis II (I-cell disease) |
GNPTAB
| AR | Severe infantile onset, progressive neurologic deterioration, skeletal deformities (incl dysostosis multiplex), postnatal growth restriction, cardiac involvement, skin thickening, recurrent ear infections | Severe contractures (although joint mobility issues may be seen in MSD) |
Krabbe disease
|
GALC
| AR | Central & peripheral demyelination, progressive neurologic deterioration | Absence of: cardiac & ophthalmologic complications, skeletal involvement (incl dysostosis multiplex), ichthyosis, hydrocephalus, hepatosplenomegaly, oral & dental issues, hearing loss, recurrent ear infections, upper airway obstruction |
Alexander disease
|
GFAP
| AD | Central demyelination & hydrocephalus, progressive neurologic deterioration | Absence of: cardiac & ophthalmologic complications, skeletal involvement (incl dysostosis multiplex), ichthyosis, hepatosplenomegaly, oral & dental issues, hearing loss, recurrent ear infections, upper airway obstruction |
Canavan disease
|
ASPA
| AR | Central demyelination, progressive neurologic deterioration, macrocephaly | Absence of: cardiac & ophthalmologic complications, skeletal involvement (incl dysotosis multiplex), ichthyosis, hepatosplenomegaly, oral & dental issues, hearing loss, recurrent ear infections, upper airway obstruction |
Fucosidosis (OMIM 230000) |
FUCA1
| AR | Progressive neurologic deterioration, dysostosis multiplex, coarse facial features | Absence of: cardiac & ophthalmologic complications, ichthyosis, hepatosplenomegaly, oral & dental issues, hearing loss, recurrent ear infections, upper airway obstruction |
MPS I 1 |
IDUA
| AR | DD, skeletal involvement, growth restriction, corneal clouding, cardiac involvement, hepatosplenomegaly, dysmorphic features | Facial dysmorphic features & cardiac involvement are more prominent in MPS I. |
MPS II (Hunter syndrome) |
IDS
| XL | DD, short stature, skeletal involvement, hepatosplenomegaly, dysmorphic features | Females rarely affected; corneal clouding not a typical feature |
MPS III (Sanfilippo syndrome) (OMIM 252900, 252920, 252930, 252940) |
GNS
HGSNAT
NAGLU
SGSH
| AR | Neurodegeneration, DD, hepatosplenomegaly (<50% of persons w/Sanfilippo syndrome) | May have slower, more insidious course presenting mainly w/cognitive & neurologic signs & symptoms |
MPS IV (Morquio syndrome) (See MPS IVA, GLB1-Related Disorders.) |
GALNS
GLB1
| AR | Skeletal involvement, hearing loss, facial dysmorphic features | More severe skeletal involvement; MPS IVA does not present w/ID. |
MPS VI (Maroteaux-Lamy syndrome) (OMIM 253200) |
ARSB
| AR | Dysmorphic features, hepatosplenomegaly, short stature, corneal clouding, skeletal involvement | More severe skeletal involvement; absence of ID |
X-linked ichthyosis (OMIM 308100) |
STS
| XL | Corneal opacities, ichthyosis | Females rarely affected; absence of DD & neurodegeneration |
Chondrodysplasia punctata 1, X-linked
| ARSL (ARSE) | XLR | DD in 15%-20% of affected persons, short stature, epiphyseal stippling, cataracts, hearing loss | Females rarely affected; characteristic facial appearance; absence of neurodegeneration |
Hexosaminidase A deficiency (Tay-Sachs disease) |
HEXA
| AR | Progressive neurodegeneration, DD, spasticity, blindness, death in infancy | Cherry red spot of the fovea 2; absence of skeletal abnormalities & hepatomegaly |
Hexosaminidase A/B deficiency (Sandhoff disease) |
HEXB
| AR | Progressive neurodegeneration, DD, spasticity, blindness, death in infancy | Cherry red spot & ↑ startle response 3; hepatomegaly & skeletal abnormalities are less common than in MSD |