Megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome

MedGen UID:: 928562
•Concept ID:: C4302893
•: Disease or Syndrome

Synonyms:	MEG-PMG-MEGACC SYNDROME; Megalencephaly-Polymicrogyria- Polydactyly- Hydrocephalus (MPPH) Syndrome
SNOMED CT:	Megalencephaly, polymicrogyria, postaxial polydactyly, hydrocephalus syndrome (722036008); MPPH syndrome (722036008); MPPH (megalencephaly, polymicrogyria, polydactyly, hydrocephalus) syndrome (722036008)
Modes of inheritance:	Autosomal dominant inheritance MedGen UID: 141047 •Concept ID: C0443147 • 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 heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele. Not genetically inherited MedGen UID: 988794 •Concept ID: CN307044 • Finding Source: Orphanet clinical entity without genetic inheritance. See: This record Autosomal dominant inheritance (Orphanet) Not genetically inherited (Orphanet)

Monarch Initiative:	MONDO:0019375
OMIM® Phenotypic series:	PS603387
Orphanet:	ORPHA83473

Disease characteristics

Excerpted from the GeneReview: MPPH Syndrome

MPPH (megalencephaly-postaxial polydactyly-polymicrogyria-hydrocephalus) syndrome is a developmental brain disorder characterized by megalencephaly (brain overgrowth) with the cortical malformation bilateral perisylvian polymicrogyria (BPP). At birth the occipital frontal circumference (OFC) ranges from normal to 6 standard deviations (SD) above the mean for age, sex, and gestational age; in older individuals the range is from 3 to 10 SD above the mean. A variable degree of ventriculomegaly is seen in almost all children with MPPH syndrome; nearly 50% of individuals have frank hydrocephalus. Neurologic problems associated with BPP include oromotor dysfunction (100%), epilepsy (50%), and mild-to-severe intellectual disability (100%). Postaxial hexadactyly occurs in 50% of individuals with MPPH syndrome. [from GeneReviews]

Authors:
Ghayda Mirzaa view full author information

Additional description

From OMIM
This disorder comprises megalencephaly, hydrocephalus, and polymicrogyria; polydactyly may also be seen. There is considerable phenotypic similarity between this disorder and the megalencephaly-capillary malformation syndrome (MCAP; 602501) (summary by Gripp et al., 2009). Genetic Heterogeneity of the Megalencephaly-Polymicrogyria-Polydactyly-Hydrocephalus Syndrome See also MPPH2 (615937), caused by mutation in the AKT3 gene (611223) on chromosome 1q43-q44; and MPPH3 (615938), caused by mutation in the CCND2 gene (123833) on chromosome 12p13. http://www.omim.org/entry/603387

Term Hierarchy

GTR
MeSH

CClinical test, RResearch test, OOMIM, GGeneReviews, VClinVar

CROGVMegalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome

Genetic syndrome with corpus callosum agenesis/dysgenesis as a major feature
- Megalencephaly-polymicrogyria-postaxial polydactyly-hydrocephalus syndrome

Recent clinical studies

Etiology

Molecular Diagnosis of Mosaic Overgrowth Syndromes Using a Custom-Designed Next-Generation Sequencing Panel.

Chang F, Liu L, Fang E, Zhang G, Chen T, Cao K, Li Y, Li MM
J Mol Diagn 2017 Jul;19(4):613-624. Epub 2017 May 11 doi: 10.1016/j.jmoldx.2017.04.006. PMID: 28502725

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Diagnosis

Prenatal Ultrasound Diagnosis of Megalencephaly-Polymicrogyria-Polydactyly-Hydrocephalus Syndrome with Persistent Hyperplastic Primary Vitreous: A Case Report.

Su XR, Ma B, Zhang C, Li TG, Han BL, Wu WR, Nie F
Fetal Diagn Ther 2024;51(2):154-158. Epub 2023 Nov 26 doi: 10.1159/000535509. PMID: 38008077

Maternal mosaicism underlies the inheritance of a rare germline AKT3 variant which is responsible for megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome in two Roma half-siblings.

Szalai R, Melegh BI, Till A, Ripszam R, Csabi G, Acharya A, Schrauwen I, Leal SM, Komoly S, Kosztolanyi G, Hadzsiev K
Exp Mol Pathol 2020 Aug;115:104471. Epub 2020 May 21 doi: 10.1016/j.yexmp.2020.104471. PMID: 32446860

Overgrowth Syndromes Caused by Somatic Variants in the Phosphatidylinositol 3-Kinase/AKT/Mammalian Target of Rapamycin Pathway.

Akgumus G, Chang F, Li MM
J Mol Diagn 2017 Jul;19(4):487-497. Epub 2017 May 11 doi: 10.1016/j.jmoldx.2017.04.001. PMID: 28502730

MEGALENCEPHALY, POLYMICROGYRIA, POLYDACTYLY AND HYDROCEPHALUS (MPPH) SYNDROME: A NEW CASE WITH OCCIPITAL ENCEPHALOCELE AND CLEFT PALATE.

Demir N, Peker E, Gülşen I, Kaba S, Tuncer O
Genet Couns 2015;26(4):381-5. PMID: 26852507

Four-year follow-up of megalencephaly, polymicrogyria, postaxial polydactyly and hydrocephalus (MPPH) syndrome.

Zamora TG, Roberts KD
BMJ Case Rep 2013 Oct 3;2013 doi: 10.1136/bcr-2012-007826. PMID: 24092603 Free PMC Article

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