Congenital disorder of glycosylation, type IIq(CDG2Q; CDGIIq)

MedGen UID:: 1390458
•Concept ID:: C4479353
•: Disease or Syndrome

Synonym:	CDG IIq
SNOMED CT:	COG2-related congenital disorder of glycosylation (1197753005); COG2-CDG - component of oligomeric golgi complex 2 - congenital disorder of glycosylation (1197753005); Component of oligomeric golgi complex 2-related congenital disorder of glycosylation (1197753005)
Modes of inheritance:	Autosomal recessive inheritance MedGen UID: 141025 •Concept ID: C0441748 • Intellectual Product Source: Orphanet A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele). Autosomal recessive inheritance (Orphanet)

Gene (location): Gene(s) directly associated with this condition or phenotype.	COG2 (1q42.2)

Monarch Initiative:	MONDO:0054559
OMIM®:	617395
Orphanet:	ORPHA435934

Definition

A rare congenital disorder of glycosylation caused by mutations in the COG2 gene and with characteristics of normal presentation at birth, followed by progressive deterioration with postnatal microcephaly, developmental delay, intellectual disability, seizures, spastic quadriplegia, liver dysfunction, hypocupremia and hypoceruloplasminemia in the first year of life. Diffuse cerebral atrophy and thin corpus callosum may be observed on brain MRI. [from SNOMEDCT_US]

Clinical features

From HPO

Hypoplasia of the corpus callosum

MedGen UID:: 138005
•Concept ID:: C0344482
•: Congenital Abnormality

Underdevelopment of the corpus callosum.

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Spastic tetraplegia

MedGen UID:: 98433
•Concept ID:: C0426970
•: Disease or Syndrome

Spastic paralysis affecting all four limbs.

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Global developmental delay

MedGen UID:: 107838
•Concept ID:: C0557874
•: Finding

A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.

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Diffuse cerebral atrophy

MedGen UID:: 108958
•Concept ID:: C0598275
•: Finding

Diffuse unlocalised atrophy affecting the cerebrum.

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Generalized tonic seizure

MedGen UID:: 322935
•Concept ID:: C1836508
•: Disease or Syndrome

A generalized tonic seizure is a type of generalized motor seizure characterized by bilateral limb stiffening or elevation, often with neck stiffening without a subsequent clonic phase. The tonic activity can be a sustained abnormal posture, either in extension or flexion, sometimes accompanied by tremor of the extremities.

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Small pituitary gland

MedGen UID:: 868479
•Concept ID:: C4022873
•: Anatomical Abnormality

An abnormally decreased size of the pituitary gland.

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Hypotonia

MedGen UID:: 10133
•Concept ID:: C0026827
•: Finding

Hypotonia is an abnormally low muscle tone (the amount of tension or resistance to movement in a muscle). Even when relaxed, muscles have a continuous and passive partial contraction which provides some resistance to passive stretching. Hypotonia thus manifests as diminished resistance to passive stretching. Hypotonia is not the same as muscle weakness, although the two conditions can co-exist.

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Secondary microcephaly

MedGen UID:: 608952
•Concept ID:: C0431352
•: Finding

Head circumference which falls below 2 standard deviations below the mean for age and gender because of insufficient head growth after birth.

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Decreased circulating ceruloplasmin concentration

MedGen UID:: 472980
•Concept ID:: C0240997
•: Finding

Decreased concentration of ceruloplasmin in the blood.

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Decreased circulating copper concentration

MedGen UID:: 488831
•Concept ID:: C0268070
•: Disease or Syndrome

A reduced concentration of copper in the blood.

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Elevated circulating hepatic transaminase concentration

MedGen UID:: 338525
•Concept ID:: C1848701
•: Finding

Elevations of the levels of SGOT and SGPT in the serum. SGOT (serum glutamic oxaloacetic transaminase) and SGPT (serum glutamic pyruvic transaminase) are transaminases primarily found in the liver and heart and are released into the bloodstream as the result of liver or heart damage. SGOT and SGPT are used clinically mainly as markers of liver damage.

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Abnormal glycosylation