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Hypodysplasia of the corpus callosum

MedGen UID:
Concept ID:
HPO: HP:0006849


Developmental defect characterized by a small and malformed corpus callosum. [from HPO]

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVHypodysplasia of the corpus callosum

Conditions with this feature

Mosaic variegated aneuploidy syndrome 1
MedGen UID:
Concept ID:
Disease or Syndrome
Mosaic variegated aneuploidy (MVA) syndrome is a rare disorder in which some cells in the body have an abnormal number of chromosomes instead of the usual 46 chromosomes, a situation known as aneuploidy. Most commonly, cells have an extra chromosome, which is called trisomy, or are missing a chromosome, which is known as monosomy. In MVA syndrome, some cells are aneuploid and others have the normal number of chromosomes, which is a phenomenon known as mosaicism. Typically, at least one-quarter of cells in affected individuals have an abnormal number of chromosomes. Because the additional or missing chromosomes vary among the abnormal cells, the aneuploidy is described as variegated.\n\nThere are at least three types of MVA syndrome, each with a different genetic cause. Type 1 is the most common and displays the classic signs and symptoms described above. Type 2 appears to have slightly different signs and symptoms than type 1, although the small number of affected individuals makes it difficult to define its characteristic features. Individuals with MVA syndrome type 2 grow slowly before and after birth; however, their head size is typically normal. Some people with MVA syndrome type 2 have unusually short arms. Individuals with MVA syndrome type 2 do not seem to have an increased risk of cancer. Another form of MVA syndrome is characterized by a high risk of developing Wilms tumor. Individuals with this form may also have other signs and symptoms typical of MVA syndrome type 1.\n\nIn MVA syndrome, growth before birth is slow (intrauterine growth restriction). After birth, affected individuals continue to grow at a slow rate and are shorter than average. In addition, they typically have an unusually small head size (microcephaly). Another common feature of MVA syndrome is an increased risk of developing cancer in childhood. Cancers that occur most frequently in affected individuals include a cancer of muscle tissue called rhabdomyosarcoma, a form of kidney cancer known as Wilms tumor, and a cancer of the blood-forming tissue known as leukemia.\n\nLess commonly, people with MVA syndrome have eye abnormalities or distinctive facial features, such as a broad nasal bridge and low-set ears. Some affected individuals have brain abnormalities, the most common of which is called Dandy-Walker malformation. Intellectual disability, seizures, and other health problems can also occur in people with MVA syndrome.

Recent clinical studies


Khalaf-Nazzal R, Fasham J, Inskeep KA, Blizzard LE, Leslie JS, Wakeling MN, Ubeyratna N, Mitani T, Griffith JL, Baker W, Al-Hijawi F, Keough KC, Gezdirici A, Pena L, Spaeth CG, Turnpenny PD, Walsh JR, Ray R, Neilson A, Kouranova E, Cui X, Curiel DT, Pehlivan D, Akdemir ZC, Posey JE, Lupski JR, Dobyns WB, Stottmann RW, Crosby AH, Baple EL
Am J Hum Genet 2022 Nov 3;109(11):2068-2079. Epub 2022 Oct 24 doi: 10.1016/j.ajhg.2022.09.012. PMID: 36283405Free PMC Article

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