Meckel syndrome
Other names	Meckel–Gruber syndrome,Gruber syndrome,Dysencephalia splanchnocystica
Embryos with mutation in MKS1KRC, a cause of Meckel syndrome.
Specialty	Medical genetics
Named after	Johann Meckel Georg Gruber

Meckel-Gruber syndrome is a rare,lethalciliopathicgenetic disorder, characterized byrenalcysticdysplasia,central nervous system malformations (occipital encephalocele),polydactyly (postaxial),hepatic developmental defects, andpulmonary hypoplasia due tooligohydramnios.^[1][2] Meckel–Gruber syndrome is named forJohann Meckel and Georg Gruber.^[3][4][5] In 2 recorded cases of MGS survival beyondinfancy, they survived until 14 and 28 months.^[2]

Meckel–Gruber syndrome (MKS) is anautosomalrecessivelethalmalformation. Two MKSgenes,MKS1 andMKS3, have been associated with the disorder. A study done recently has described thecellular,sub-cellular and functional characterization of the novelproteins,MKS1 and meckelin, encoded by thesegenes.^[6] The malfunction in the production of theseproteins is mainly responsible for this lethal disorder.^{[citation needed]}

Recent findings ingenetic research have suggested that a large numberphenotypically varying raregenetic disorders may share a commongenotypicalroot cause. As Meckel–Gruber syndrome is aciliopathy, it may be related to other knownciliopathies, such asprimary ciliary dyskinesia,Bardet–Biedl syndrome,polycystic kidney andliver disease,nephronophthisis,Alström syndrome, and some forms ofretinal degeneration.^[7] The MKS1 gene has been identified as being associated with ciliopathy.^[8]

Dysplastickidneys areprevalent in over 95% of all identified cases. When this occurs,microscopiccysts develop within the kidney and slowly destroy it, causing it to enlarge up to 10 or 20 times its original size. The level ofamniotic fluid within thewomb may be significantly altered or remain normal, and a normal level of fluid should not be criteria for exclusion ofdiagnosis.^{[citation needed]}

Occipitalencephalocele is present in 60% to 80% of all cases, and postaxialpolydactyly is present in 55% to 75% of the total number of identified cases.Bowing or shortening of the limbs are also common.^{[citation needed]}

Finding at least two of the threephenotypic features of the classical triad in the presence of normalkaryotype indicates a high likelihood of Meckel-Gruber Syndrome. Regularultrasounds and proactive prenatal care can usually detectsymptoms early on inpregnancy.^{[citation needed]}

There is nocure for Meckel-Gruber syndrome. Treatment is limited tosymptom management andpalliative care.^[9]

The disease is lethal. Most infants that are notstillborn with Meckel-Gruber syndrome die within hours to days of birth due torenal failure andlunghypoplasia.^[9][10] The longest survival time reported in medical literature is 28 months.^[11]

While not precisely known, it is estimated that the general rate ofincidence, according to Bergsma,^[12] for Meckel-Gruber syndrome is 0.02 per 10,000births. According to another study done six years later, the incidence rate could vary from 0.07 to 0.7 per 10,000 births.^[13]

This syndrome is aFinnish heritage disease. Itsfrequency is much higher inFinland, where the incidence is as high as 1.1 per 10,000 births. It is estimated that Meckel-Gruber syndrome accounts for 5% of allneural tube defects there.^[14] TheLeicestershire Perinatal Mortality Survey for the years 1976 to 1982 had found high incidence of Meckel-Gruber syndrome inGujaratiIndian immigrants.^[15]

• Autosomal recessive disorders
• Ciliopathy
• Congenital disorders of nervous system
• Congenital disorders of digestive system
• Congenital disorders of urinary system
• Rare syndromes
• Diseases named after discoverers

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• Short description is different from Wikidata
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• Articles with unsourced statements from November 2020
• Articles with unsourced statements from October 2011