Dysplastic kidneys are prevalent 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 of amniotic fluid within the womb may be significantly altered or remain normal, and a normal level of fluid should not be criteria for exclusion of diagnosis.[citation needed]
Occipitalencephalocele is present in 60% to 80% of all cases, and postaxial polydactyly is present in 55% to 75% of the total number of identified cases. Bowing or shortening of the limbs are also common.[citation needed]
The disease is lethal. Most infants that are not stillborn with Meckel-Gruber syndrome die within hours to days of birth due to renal failure and lunghypoplasia.[9][10] The longest survival time reported in medical literature is 28 months.[11]
Incidence
While not precisely known, it is estimated that the general rate of incidence, according to Bergsma,[12] for Meckel-Gruber syndrome is 0.02 per 10,000 births. 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 a Finnish heritage disease. Its frequency is much higher in Finland, where the incidence is as high as 1.1 per 10,000 births. It is estimated that Meckel-Gruber syndrome accounts for 5% of all neural tube defects there.[14] The Leicestershire Perinatal Mortality Survey for the years 1976 to 1982 had found high incidence of Meckel-Gruber syndrome in GujaratiIndian immigrants.[15]
^J. F. Meckel. Beschreibung zweier durch sehr ähnliche Bildungsabweichungen entstellter Geschwister. Deutsches Archiv für Physiologie, 1822, 7: 99–172.
^G. B. Gruber. Beiträge zur Frage "gekoppelter" Missbildungen (Akrocephalossyndactylie und Dysencephalia splancnocystica. Beitr path Anat, 1934, 93: 459–476.
^Badano, Jose L.; Norimasa Mitsuma; Phil L. Beales; Nicholas Katsanis (Sep 2006). "The Ciliopathies : An Emerging Class of Human Genetic Disorders". Annual Review of Genomics and Human Genetics. 7: 125–148. doi:10.1146/annurev.genom.7.080505.115610. PMID16722803.
^Bergsma, D. (1979). "Birth Defects". Atlas and Compendium. London: Macmillan Press.
^Salonen, R.; Norio, R.; Reynolds, James F. (1984). "The Meckel syndrome: Clinicopathological Findings in 67 Patients". American Journal of Medical Genetics. 18 (4): 671–689. doi:10.1002/ajmg.1320180414. PMID6486167.