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ORPHA:397941Disease
Also called Carbohydrate deficient glycoprotein syndrome type II due to MAN1B1 deficiency · Congenital disorder of glycosylation type 2 due to MAN1B1 deficiency · Congenital disorder of glycosylation type II due to MAN1B1 deficiency · Intellectual disability-truncal obesity syndrome
What it is
MAN1B1-CDG is a form of congenital disorders of N-linked glycosylation characterized by intellectual disability, delayed motor development, hypotonia and truncal obesity. Additional features include slight facial dysmorphism (hypertelorism, downslanting palpebral fissures, large, low-set ears, hypoplastic nasolabial fold, thin upper lip), hypermobility of the joints and skin laxity. The disease is caused by mutations in the gene MAN1B1 (9q34.3).
Key facts
- Prevalence
- <1 / 1 000 000
- Age of onset
- Childhood, Infancy
- Inheritance
- Autosomal recessive
- Classified as
- Disease
Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.
Signs and symptoms
Very common80–99%
4Common30–79%
9Sometimes5–29%
29- Abnormal position of hair whorl
- Atypical behavior
- Autism
- Broad-based gait
- Cerebellar hypoplasia
- Cutis laxa
- Dolichocephaly
- Frontal bossing
and 21 more in this range
Rare1–4%
11- 2-3 toe syndactyly
- Clinodactyly of the 5th finger
- Eclabion
- Epicanthus
- Flat occiput
- Long eyelashes
- Long face
- Multiple cafe-au-lait spots
and 3 more in this range
These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.
Gene
ICD-10 codes
ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Cross-references
Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.
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