congenital disorder of glycosylation, type Ibb

Summary

congenital disorder of glycosylation, type Ibb (MONDO:0800353) is a disease with 1 cohort gene.

At a glance

• Cohort genes: 1
• ClinVar variants: 2

Clinical features

No curated clinical features (Orphanet) for this disease.

Identifiers

Disease identifiers

Field	Value
Canonical name	congenital disorder of glycosylation, type Ibb
Mondo ID	MONDO:0800353
UMLS	C4693133
MedGen	1637983
GARD	0026518
Is cancer (heuristic)	no

Also known as: CDG1BB

Data availability: 2 ClinVar variants.

Disease family

Classification path: disease › human disease › disease by etiologic mechanism › disease of genetic or genomic mechanism › hereditary disease › inborn errors of metabolism › congenital disorder of glycosylation › congenital disorder of glycosylation, type Ibb

Related subtypes (24): congenital disorder of glycosylation type I, congenital disorder of glycosylation type II, Larsen-like syndrome, B3GAT3 type, Ehlers-Danlos syndrome, musculocontractural type, temtamy preaxial brachydactyly syndrome, progressive myoclonic epilepsy type 3, autosomal recessive limb-girdle muscular dystrophy type 2P, seizures-scoliosis-macrocephaly syndrome, disorder of protein N-glycosylation, disorder of protein O-glycosylation, inborn disorder of glycosphingolipid and glycosylphosphatidylinositol anchor glycosylation, disorder of multiple glycosylation, XYLT1-congenital disorder of glycosylation, congenital muscular dystrophy with intellectual disability, congenital disorder of glycosylation syndrome type 4, congenital disorder of glycosylation with defective fucosylation, SLC10A7-congenital disorder of glycosylation, ALG14-congenital disorder of glycosylation, B3GALT6-congenital disorder of glycosylation, A4GALT-congenital disorder of glycosylation, FAM20B-congenital disorder of glycosylation, ALG10-congenital disorder of glycosylation, congenital disorder of glycosylation, type Iw, autosomal dominant, congenital disorder of glycosylation, type 1DD

Genetics & variants

GWAS landscape

No GWAS associations recorded — common-variant (GWAS) studies don’t cover this disease (typical for Mendelian / rare diseases). See the curated gene cohort and Mendelian overlap below.

Variant details and genetic-evidence tiers

ClinVar germline variants

2 retrieved; paginated sample, class counts are floors:

1 pathogenic, 1 likely pathogenic

ClinVar	Variant (HGVS)	Gene	Classification	Review
488194	NM_205861.3(DHDDS):c.192G>A (p.Trp64Ter)	DHDDS	Pathogenic	no assertion criteria provided
488195	NM_205861.3(DHDDS):c.441-24A>G	DHDDS	Likely pathogenic	criteria provided, multiple submitters, no conflicts

Genes & proteins

Mendelian disease overlap and somatic drivers

GenCC: 0 · Orphanet: 2 · OMIM-shared: 0 · Dual-evidence (GWAS+Mendelian): 0

Orphanet rare-disease linkage (cohort genes)

Gene	Orphanet ID	Rare disease
DHDDS	Orphanet:442835	Non-specific early-onset epileptic encephalopathy
DHDDS	Orphanet:791	Retinitis pigmentosa

Cohort genes → proteins

1 cohort genes, 1 distinct canonical proteins.

Evidence partition

Subset	Genes
multi_evidence	1

Cohort genes (full)

Symbol	HGNC	Ensembl	UniProt	Name	Evidence
DHDDS	HGNC:20603	ENSG00000117682	Q86SQ9	Dehydrodolichyl diphosphate synthase complex subunit DHDDS	clinvar

Cohort function summary

Lead sentence per gene, UniProt-curated.

Symbol	Protein name	Function (lead sentence)
DHDDS	Dehydrodolichyl diphosphate synthase complex subunit DHDDS	With NUS1, forms the dehydrodolichyl diphosphate synthase (DDS) complex, an essential component of the dolichol monophosphate (Dol-P) biosynthetic machinery.

Protein-family classification

Druggable: 1 · Difficult: 0 · Unknown: 0 · Druggable fraction: 1.0

Family distribution

Cohort families vs a genome-wide background (hypergeometric, BH-FDR; fold = observed/expected). Counts kept; sorted by enrichment, so the catch-all Other/Unknown bucket no longer leads.

Family	Genes	Fold	FDR
Enzyme (other)	1	12.0×	0.083

Per-gene assignment

Symbol	Family	Druggable?	EC	InterPro (top 3)
DHDDS	Enzyme (other)	yes	2.5.1.87	UPP_synth-like, UPP_synth-like_CS, UPP_synth-like_sf

Expression context

Cohort genes with no expression data: 0.

1 cohort gene are a single-cell marker in ≥1 SCXA experiment.

Breadth distribution (Bgee present_calls)

Bucket	Genes
narrow (1-5 tissues)	0
moderate (6-20)	0
broad (>20)	1
unknown	0

Top tissues across cohort

Tissue	Cohort genes
cerebellar cortex	1
cerebellar hemisphere	1
sperm	1

Per-gene tissue summary (top 30)

Symbol	Bgee breadth	FANTOM5 breadth	SCXA	Top tissues
DHDDS	259	ubiquitous	marker	sperm, cerebellar cortex, cerebellar hemisphere

Protein interactions among cohort

Intra-cohort edges: 0.

Hub genes (top 10 by interactor count)

Symbol	Interactor count
DHDDS	2,049

Structural data

PDB: 1 · AlphaFold-only: 0 · No structure: 0

Cohort genes with PDB structures (top 30)

Symbol	UniProt	PDB entries
DHDDS	Q86SQ9	9

Function

Pathway analysis

Distinct Reactome pathways touched by cohort: 2. Enrichment computed across 1 evidence-associated genes (1 with Reactome annotation).

Pathways by enrichment

Over-representation of cohort genes vs the genome-wide background (hypergeometric test, Benjamini-Hochberg FDR; fold = observed/expected over 1 annotated cohort genes). Counts and members are kept as ground-truth; sorted by enrichment.

Pathway	Cohort genes	Fold	FDR	Sample cohort genes
Defective DHDDS causes RP59	1	5710.0×	4e-04	DHDDS
Synthesis of dolichyl-phosphate	1	1631.4×	6e-04	DHDDS

GO biological processes by enrichment

Over-representation of cohort genes vs the genome-wide background (hypergeometric test, Benjamini-Hochberg FDR; fold = observed/expected over 1 annotated cohort genes). Counts and members are kept as ground-truth; sorted by enrichment.

GO term	Cohort genes	Fold	FDR	Sample cohort genes
polyprenol biosynthetic process	1	16852.0×	2e-04	DHDDS
dolichyl diphosphate biosynthetic process	1	8426.0×	2e-04	DHDDS
dolichyl monophosphate biosynthetic process	1	1872.4×	5e-04	DHDDS

Therapeutics

Drug target analysis

Approved (phase 4): 0 · Phase ≥3: 0 · Phased (≥1): 0 · Undrugged: 1

Druggability breadth: 0 of 1 evidence-associated genes (0%) have a ChEMBL target (buckets above are over the deeply-mined display cohort).

Top cohort targets by molecule count

Symbol	Molecules	Max phase
DHDDS	0	0

Bioactivity and enzyme data

Enzyme cohort genes (≥1 EC): 1.

Cohort enzymes (BRENDA EC)

Symbol	EC numbers	Names
DHDDS	2.5.1.87	ditrans,polycis-polyprenyl diphosphate synthase [(2E,6E)-farnesyl diphosphate specific]

Pharmacogenomics

Cohort genes with a PharmGKB record: 1; with CPIC/DPWG dosing guidelines: 0.

No cohort gene has a CPIC/DPWG genotype-guided dosing guideline (PharmGKB).

Chemical tractability of cohort targets

0 approved/phased compounds have measured bioactivity against a cohort gene (and aren’t yet in disease-level trials). This is a research / tractability signal, NOT a therapeutic recommendation — a bioactivity row often reflects off-target or screening binding (e.g. promiscuous kinase inhibitors against a cohort kinase), implying no disease mechanism.

Druggability pyramid

Cohort genes binned by druggability tier (high → low):

Tier	Definition	Genes	Symbols
A	Approved (phase 4 drug)	0
B	Phased (≥1) drug, not yet approved	0
C	Druggable family + PDB, no drug	1	DHDDS
D	Druggable family + AlphaFold only, no drug	0
E	Difficult family or no structure, no drug	0

Undrugged target profiles

1 cohort genes are undrugged. Ranked by ‘starting-point quality’ (assay depth + drugged-partner adjacency).

Symbol	ChEMBL assays	Drugged partners (top 3)
DHDDS	0	—

Clinical trials & evidence

Clinical trials

Clinical trials: 0.