GTR Home > Conditions/Phenotypes > Carbohydrate-deficient glycoprotein syndrome type I

Disease characteristics

Excerpted from the GeneReview: PMM2-CDG (CDG-Ia)
PMM2-CDG (CDG-Ia) (previously known as congenital disorder of glycosylation type 1a), the most common of a group of disorders of abnormal glycosylation of N-linked oligosaccharides, is divided into three stages: infantile multisystem, late-infantile and childhood ataxia-intellectual disability, and adult stable disability. The three stages notwithstanding, clinical presentation and course are highly variable, ranging from infants who die in the first year of life to mildly involved adults. Clinical presentations tend to be similar in siblings. In the infantile multisystem stage, infants show axial hypotonia, hyporeflexia, esotropia, and developmental delay; feeding problems, vomiting, and diarrhea with failure to thrive; and impaired growth. Subcutaneous fat may be excessive over the buttocks and suprapubic region. Two distinct clinical presentations are observed: (1) a non-fatal neurologic form with strabismus, psychomotor retardation, and cerebellar hypoplasia in infancy followed by neuropathy and retinitis pigmentosa in the first or second decade and (2) a neurologic-multivisceral form with approximately 20% mortality in the first year of life. The late-infantile and childhood ataxia-intellectual disability stage, with onset between age three and ten years, is characterized by hypotonia, ataxia, severely delayed language and motor development, inability to walk, and IQ of 40 to 70; other findings include stroke-like episodes or transient unilateral loss of function, retinitis pigmentosa, joint contractures, and skeletal deformities. In the adult stable disability stage, intellectual ability is stable; peripheral neuropathy is variable, thoracic and spinal deformities progress, and premature aging is observed; females lack secondary sexual development and males may exhibit decreased testicular volume. Hyperglycemia-induced growth hormone release, hyperprolactinemia, insulin resistance, and coagulopathy may occur. An increased risk of deep venous thrombosis is present.

Available tests

38 tests are in the database for this condition. Compare labs offering these tests.

Check Associated genes and Related conditions for additional relevant tests.

Associated genes

Clinical features

  • Proteinuria
  • Muscle weakness
  • Prolonged prothrombin time
  • Hyporeflexia
  • Hypoalbuminemia
  • Prolonged partial thromboplastin time
  • Abnormality of the amniotic fluid
  • IgA deficiency
  • Prominent forehead
  • Kyphosis
  • Microcephaly
  • IgG deficiency
  • Nonimmune hydrops fetalis
  • Stroke-like episodes
  • Olivopontocerebellar hypoplasia
  • Proximal tubulopathy
  • Abnormal subcutaneous fat tissue distribution
  • Macrotia
  • Seizure
  • Diarrhea
  • Nystagmus
  • Osteopenia
  • Renal cyst
  • Failure to thrive
  • Feeding difficulties in infancy
  • Vomiting
  • Hypothyroidism
  • Nephrotic syndrome
  • Thin upper lip vermilion
  • Retinitis pigmentosa
  • Esotropia
  • Hypergonadotropic hypogonadism
  • Ataxia
  • Muscular hypotonia
  • Global developmental delay
  • Polyneuropathy
  • Flexion contracture
  • Hepatic fibrosis
  • Hepatic steatosis
  • Primary ovarian failure
  • Cardiomyopathy
  • Pericardial effusion
  • Thrombocytosis
  • Reduced factor XI activity
  • Reduced antithrombin III activity
  • Hepatomegaly
  • Elevated hepatic transaminases
  • Hypocholesterolemia
  • Inverted nipples
  • Type I transferrin isoform profile
  • Depressed nasal bridge
Show all (51)

IMPORTANT NOTE: NIH does not independently verify information submitted to the GTR; it relies on submitters to provide information that is accurate and not misleading. NIH makes no endorsements of tests or laboratories listed in the GTR. GTR is not a substitute for medical advice. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.

Write to the Help Desk