Meckel syndrome is an autosomal recessive disorder characterized by a combination of renal cysts and variably associated features including developmental anomalies of the central nervous system (typically encephalocele), hepatic ductal dysplasia and cysts, and polydactyly.
Meckel-Gruber syndrome (MKS) (OMIM 24900) is a lethal, rare, autosomal recessive condition mapped to chromosomes 17q21-24, 11q13, and 8q24.
This mapping suggests genetic heterogeneity in MKS. The triad of occipital encephalocele, large polycystic kidneys, and postaxial polydactyly characterizes MKS. Associated abnormalities include oral clefting, genital anomalies, CNS malformations, and liver fibrosis.
Pulmonary hypoplasia is the leading cause of death. Improvements in ultrasonography have enabled prenatal diagnosis as early as 10 weeks’ gestation.
Failure of mesodermal induction has been suggested to cause MKS. The induction cascades of early morphogenesis involve numerous growth factors, homeo box genes, and paired domain genes.
Synopsis
variable prenatal growth deficiency
craniofacial anomalies
- microcephaly
- sloping forehead
- micrognathia
- low-set ears
- microphthalmia
- hypotelorism
- hypertelorism
- iris coloboma
- cleft palate
- cleft lip
- lobulated tongue
- natal teeth
- macrostomia
- short neck
- webbed neck
cardiac anomalies
- cardiac septal defects
- coarctation of aorta
- patent ductus arteriosus
cleft epiglottis
hepatic anomalies (20%) (11000335)
- intrahepatic bile duct anomalies
- ductal plate malformation (DPM) (congenital hepatic fibrosis)
- reactive biliary neoductules proliferation (reactive bile duct proliferation)
- bile duct dilatation
- arrested development of the intrahepatic biliary system (biliary cylinders)
- reactive portal fibrosis
- portal fibrous vascular obliteration
splenic anomalies
- splenomegaly
- asplenia
- accessory spleen
- polysplenia (3068988)
single umbilical artery
omphalocele
digestive anomalies
- intestinal malrotation
- imperforate anus (anal imperforation)
genital anomaies
- small genitalia
- ambiguous genitalia
- cryptorchidism
- uterine abnormalities
renal anomalies
- renal cystic dysplasia with cystic kidneys
- renal agenesis
- duplicated ureters
-
oligohydramnios sequence
- Potter-like facies
- oligohydramnios
- pulmonary hypoplasia
hypoplastic bladder
limb anomalies
- bowed long bones
- postaxial polydactyly
- syndactyly
- clinodactyly
- talipes
nervous system anomalies
- microcephaly
- neural tube defects (NTDs)
- Arnold-Chiari malformation
- hydrocephalus
- Dandy-Walker malformation (15503488, 10649795, 8905203, 8867663, 8368252, 2063927, 1867280, 7702098)
- cerebral hypoplasia
- cerebellar hypoplasia
- olfactory lobe absence
- absence of corpus callosum
- optic tract agenesis
adrenal hypoplasia
breech presentation
perinatal death
placental enlargement
Etiology
Several loci for Meckel syndrome have been mapped:
MKS1 : mutation in gene MKS1 on 17q21-q24, encoding a component of the flagellar apparatus basal body proteome (MIM.609883).
MKS2 (MIM.603194) on 11q
MKS3 on 8q : germline mutation in gene TMEM67 encoding the transmembrane protein meckelin (MIM.609884)
MKS4 : CEP290 (NPHP6) germline mutations (17564974)
Differential diagnosis
Bardet-Bield syndrome (BBS)
hydrolethalus syndrome (MIM.236680)
Case records
Differential diagnosis
Bardet-Bield syndrome (BBS)
Goldston syndrome
Miranda syndrome
References
Baala L, Audollent S, Martinovic J, Ozilou C, Babron MC, Sivanandamoorthy S, Saunier S, Salomon R, Gonzales M, Rattenberry E, Esculpavit C, Toutain A, Moraine C, Parent P, Marcorelles P, Dauge MC, Roume J, Merrer ML, Meiner V, Meir K, Menez F, Beaufrere AM, Francannet C, Tantau J, Sinico M, Dumez Y, Macdonald F, Munnich A, Lyonnet S, Gubler MC, Genin E, Johnson CA, Vekemans M, Encha-Razavi F, Attie-Bitach T. Pleiotropic Effects of CEP290 (NPHP6) Mutations Extend to Meckel Syndrome. Am J Hum Genet. 2007 Jul;81(1):170-9. PMID: 17564974
Karmous-Benailly H, Martinovic J, Gubler MC, Sirot Y, Clech L, Ozilou C, Auge J, Brahimi N, Etchevers H, Detrait E, Esculpavit C, Audollent S, Goudefroye G, Gonzales M, Tantau J, Loget P, Joubert M, Gaillard D, Jeanne-Pasquier C, Delezoide AL, Peter MO, Plessis G, Simon-Bouy B, Dollfus H, Le Merrer M, Munnich A, Encha-Razavi F, Vekemans M, Attie-Bitach T. Antenatal presentation of bardet-biedl syndrome may mimic meckel syndrome. Am J Hum Genet. 2005 Mar;76(3):493-504. PMID: 15666242
Sergi C, Adam S, Kahl P, Otto HF. Study of the malformation of ductal plate of the liver in Meckel syndrome and review of other syndromes presenting with this anomaly. Pediatr Dev Pathol. 2000 Nov-Dec;3(6):568-83. PMID: 11000335
Blankenberg, T. A.; Ruebner, B. H.; Ellis, W. G.; Bernstein, J.; Dimmick, J. E. : Pathology of renal and hepatic anomalies in Meckel syndrome. Am. J. Med. Genet. Suppl. 3: 395-410, 1987.
Reviews
Katsanis N. Ciliary proteins and exencephaly. Nat Genet. 2006 Feb;38(2):135-6. PMID: 16444248
Hildebrandt F, Otto E. Cilia and centrosomes: a unifying pathogenic concept for cystic kidney disease? Nat Rev Genet. 2005 Dec;6(12):928-40. PMID: 16341073
Johnson CA, Gissen P, Sergi C. Molecular pathology and genetics of congenital hepatorenal fibrocystic syndromes. J Med Genet. 2003 May;40(5):311-9. PMID: 12746391
Salonen R, Paavola P. Meckel syndrome. J Med Genet. 1998 Jun;35(6):497-501. PMID: 9643292