Cleft Lip And Tooth Formation
Legal firms across the country are investigating cases involving birth defects in children and certain prescription drugs. One of these birth defects is Cleft Lip, and the amount of research surrounding this issue is pretty vast. One interesting study is called, A review of tooth formation in children with cleft lip/palate by Reijo Ranta D.D,クリスチャンルブタン.S., Dr. Odont – American Journal of Orthodontics and Dentofacial Orthopedics Volume 90, Issue 1, July 1986, Pages 11-18. Here is an excerpt: Abstract – The literature on tooth formation in children with cleft lip and/or palate is reviewed. The main focus of interest is the association of cleft type and dental abnormalities in number, size, shape, timing of formation, and eruption and cause of the abnormalities. The upper lateral incisor is the most susceptible to injury in the area of cleft in both deciduous and permanent dentitions. This tooth is affected in most instances, even in the cases of microforms of the cleft lip. The prevalence of hypodontia increases strongly with the severity of cleft. More teeth are congenitally missing from the upper jaw than from the lower jaw; however, in the permanent dentition both jaws are affected. Very high prevalence of hypodontia are observed in connection with the Van der Woude syndrome associated with cleft and with the Pierre Robin anomaly,クリスチャン. Hypodontia is similarly prevalent in subjects with isolated cleft palate with and without a positive family history of clefts. The prevalence of hypodontia varies largely in different populations,クリスチャン. Asymmetric formation of the contralateral teeth is a milder form of hypodontia.
Another interesting study is called, Studies of the Candidate Genes TGFB2, MSX1, TGFA, and TGFB3 in the Etiology of Cleft Lip and Palate in the Philippines – The Cleft Palate-Craniofacial Journal: January 1997, Vol,クリスチャンルブタン. 34, No. 1, pp. 1-6. by Andrew C. Lidral, D.D.S., Jeffrey C. Murray, M.D., Kenneth H. Buetow, Ph.D., Ann M. Basart, Heidi Schearer, Rita Shiang, Ph.D., Avelina Naval, Eriberto Layda, M.D., Kathy Magee, R.N., and William Magee, M.D., D.D.S. Here is an excerpt: Abstract – Population-based candidate-gene studies can be an effective strategy for identifying genes involved in the etiology of disorders where family-based linkage studies are compromised by lack of access to affected members, low penetrance, and/or genetic heterogeneity. We evaluated association data for four candidate genes using a population from the Philippines that is genetically separate from previously studied Caucasian populations. Case ascertainment was made possible by collaboration with Operation Smile, a volunteer medical organization, which facilitated identification of a large number of cases for study. A new allelic variant of transforming growth factor-beta3 was identified to use in these studies. After exclusion of syndromic cases of cleft lip and palate, no evidence for association with previously reported allelic variants of transforming growth factor-beta2 (TGFB2), homeobox 7 (MSX1), or transforming growth factor-alpha (TGFA), or with the new TGFB3 variant was detected. Previous association studies using Caucasian populations of nonsyndromic cleft lip and/or palate (CL/P) and cleft palate only (CPO) have strongly suggested a role for TGFA in the susceptibility of clefting in humans. Exclusion of significant association in a non-Caucasian population for TGFA suggests that TGFA plays less of a role than it does in Caucasians. This may be due to multiple or different genetic and/or environmental factors contributing to the etiology of this most common craniofacial anomaly in the Philippine population.
Another interesting study is called, Familial recurrence-pattern analysis of cleft lip with or without cleft palate. By M Farrall and S Holder – Division of Molecular Medicine, Medical Research Council Clinical Research Centre, Harrow, England. Am J Hum Genet. 1992 February; 50(2): 270277. Here is an excerpt: Abstract – Cleft lip with or without cleft palate (CL/P) is a common congenital malformation with an incidence in European white populations of about 1/1,000. The familial clustering of CL/P has been extensively characterized, and epidemiological studies have proposed monogenic models (with reduced penetrance), multifactorial/threshold models, and mixed major-gene/multifactorial models to explain its inheritance. The recognition of an association between two RFLPs at the transforming growth factor alpha (TGFA) locus and CL/P supports a major-gene component to the etiology of CL/P. Risch has shown that the recurrence risk ratio lambda R (risk to relatives, vs. population prevalence) is a useful pointer to the mode of inheritance. Here we further develop the use of lambda R to analyze recurrence-risk data for CL/P. Recurrence risks for first-, second-, and third-degree relatives equate well with oligogenic models with as few as four loci. A monogenic/additive model is strongly rejected. The limited available twin data are also consistent with this model. A “major gene” interacting epistatically with an oligogenic background is shown to be a plausible alternative. Power calculations for a linkage study to map the CL/P major-risk locus suggest that a sample of 50 affected sib pairs will be adequate, but linkage to minor-risk loci will require very much larger samples.
Another interesting study is called, Associated Malformations in Infants With Cleft Lip and Palate: A Prospective, Population-based Study – PEDIATRICS Vol. 100 No. 2 August 1997, pp. 180-186 by Josef Milerad, Ola Larson, Catharina Hagberg, and Margareta Ideberg – Departments of Pediatrics and Plastic and Reconstructive Surgery, Karolinska Hospital, Stockholm, Sweden; and the Department of Orthodontics, Faculty of Odontology, Karolinska Institute, Huddinge, Sweden. Here is an excerpt: Objective. Infants with cleft lip and palate may often have other associated congenital defects although the reported incidence and the types of associated malformations vary between different studies. The purpose of this investigation was to assess the prevalence of associated malformations in a geographically defined population. Methods. The prevalence of associated malformations in infants with clefts were collected prospectively between 1975 to 1992 on all infants born in greater Stockholm, Sweden. The patient records were also compared with data from the National Malformation Registry and other hospital records if any. Conclusion. A more extensive cleft seems to be associated with a higher risk for associated malformations. Although many associated congenital defects can be detected at a physical examination, the high prevalence of congenital heart disease (16 times that of general population) may justify a routine echocardiographic screening.
We all owe a debt of gratitude to these researchers for their fine work and dedication. For more information, please read the studies in their entirety.
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