Multifactorial Mode Of Inheritance Research Articles

Genome-wide family-based study in torus palatinus affected individuals

ObjectiveTori or exostoses are bony growths that appear in different oral regions. Torus palatinus, more specifically, develop in the palate midline and can impair proper word pronunciation and hinder the fabrication and use of dentures. Even though a multifactorial inheritance model has been suggested for torus palatinus appearance, precise genetic factors involved in its etiology remain unclear. Hence, in this study we aimed to identify variants across the genome of individuals from 46 Filipino families that associate with torus palatinus. DesignAll families were composed of fishermen or landless rural dwellers who provided blood samples for DNA extraction and genotyping. A total of 3519 single nucleotide polymorphisms (SNPs) were analyzed through a transmission disequilibrium test in individuals affected by torus palatinus and their unaffected family members. ResultsFourteen SNPs showed trends for associations to the level of p < .005 threshold and several others were nominally (p < .05) associated with torus palatinus. We highlight SNP rs6582285, which is located in the CAPS2 gene, being the C allele less transmitted than the T allele in our sample. The C allele of CAPS2 rs6582285 protects from having torus palatinus whereas the other associations found were linked to an increased risk of developing the condition. ConclusionsTrends for associations were identified for several markers across the genome, supporting the hypothesis that torus palatinus has a multifactorial mode of inheritance. We hope that our study contributes to a better understanding of torus palatinus etiology and helps guide future research in examining genes for this often-overlooked condition in different populations.

Assessment of copy number variations in 120 patients with Poland syndrome.

BackgroundPoland Syndrome (PS) is a rare congenital disorder presenting with agenesis/hypoplasia of the pectoralis major muscle variably associated with thoracic and/or upper limb anomalies. Most cases are sporadic, but familial recurrence, with different inheritance patterns, has been observed. The genetic etiology of PS remains unknown. Karyotyping and array-comparative genomic hybridization (CGH) analyses can identify genomic imbalances that can clarify the genetic etiology of congenital and neurodevelopmental disorders. We previously reported a chromosome 11 deletion in twin girls with pectoralis muscle hypoplasia and skeletal anomalies, and a chromosome six deletion in a patient presenting a complex phenotype that included pectoralis muscle hypoplasia. However, the contribution of genomic imbalances to PS remains largely unknown.MethodsTo investigate the prevalence of chromosomal imbalances in PS, standard cytogenetic and array-CGH analyses were performed in 120 PS patients.ResultsFollowing the application of stringent filter criteria, 14 rare copy number variations (CNVs) were identified in 14 PS patients in different regions outside known common copy number variations: seven genomic duplications and seven genomic deletions, enclosing the two previously reported PS associated chromosomal deletions. These CNVs ranged from 0.04 to 4.71 Mb in size. Bioinformatic analysis of array-CGH data indicated gene enrichment in pathways involved in cell-cell adhesion, DNA binding and apoptosis processes. The analysis also provided a number of candidate genes possibly causing the developmental defects observed in PS patients, among others REV3L, a gene coding for an error-prone DNA polymerase previously associated with Möbius Syndrome with variable phenotypes including pectoralis muscle agenesis.ConclusionsA number of rare CNVs were identified in PS patients, and these involve genes that represent candidates for further evaluation. Rare inherited CNVs may contribute to, or represent risk factors of PS in a multifactorial mode of inheritance.Electronic supplementary materialThe online version of this article (doi:10.1186/s12881-016-0351-x) contains supplementary material, which is available to authorized users.

Evaluation of Psoriasis Genetic Risk Based on Five Susceptibility Markers in a Population from Northern Poland.

Psoriasis genetic background depends on polygenic and multifactorial mode of inheritance. As in other complex disorders, the estimation of the disease risk based on individual genetic variants is impossible. For this reason, recent investigations have been focused on combinations of known psoriasis susceptibility markers in order to improve the disease risk evaluation. Our aim was to compare psoriasis genetic risk score (GRS) for five susceptibility loci involved in the immunological response (HLA-C, ERAP1, ZAP70) and in the skin barrier function (LCE3, CSTA) between patients with chronic plaque psoriasis (n = 148) and the control group (n = 146). A significantly higher number of predisposing alleles was observed in patients with psoriasis in comparison to healthy individuals (6.1 vs. 5.2, respectively; P = 8.8×10−7). The statistical significance was even more profound when GRS weighted by logarithm odds ratios was evaluated (P = 9.9×10−14). Our results demonstrate the developed panel of five susceptibility loci to be more efficient in predicting psoriasis risk in the Polish population and to possess higher sensitivity and specificity for the disease than any of the markers analyzed separately, including the most informative HLA-C*06 allele.

Genetic background of skin barrier dysfunction in the pathogenesis of psoriasis vulgaris

Psoriasis is a common inflammatory skin disease. It is known to be a complex condition with multifactorial mode of inheritance, however the associations between particular pathogenic pathways remain unclear. A novel report on the pathogenesis of psoriasis has recently included the genetic determination of the skin barrier dysfunction. In this paper, we focus on specific genetic variants associated with formation of the epidermal barrier and their role in the complex pathogenesis of the disease.

Pedigree analysis of idiopathic epilepsy in children of South Kerala

Background and aims: Epilepsy is a major health problem in infancy and childhood. Genetic factors are implicated in the etiology of epilepsy. A familial susceptibility to seizures have been recognized but the exact mode of inheritance remains unclear. The chief objective was to determine the inheritance pattern and to correlate its prevalence among closer relatives on the basis of sex, degree of relationship and age of onset of the disease. Materials and methods: A pedigree analysis of 100 clinically diagnosed children with idiopathic epilepsy seen between 1994 and 1997 at the Paediatric Neurology Clinic of Government Medical College, Thiruvananthapuram was done. The mode of inheritance was tested according to the genetic hypothesis of segregation analysis. Results: Positive family history was observed in 49% of the probands. A high proportion of probands with an early onset of disease showed involvement of family members and a significant sex predisposition for females was obtained. Relatives of female probands were affected more than those of males. Mothers were found to transmit the disease to offsprings more than the epileptic fathers. Conclusion: The results of pedigree analysis supported the hypothesis of an autosomal multifactorial mode of inheritance, with 86% heritability and a lower threshold for the disease to manifest. The application of modern genetic principles like identification of susceptibility gene to epilepsy, linkage and association studies would advance our understanding of the etiology of seizure disorders. Genetic factors may play a major role in the predisposition of relatives to epilepsy in families of probands with idiopathic epilepsy. The present study may aid in the genetic counselling of parents with epilepsy

Pedigree Analysis of Idiopathic Epilepsy In Children of South Kerala

Abstract Background and aims: Epilepsy is a major health problem in infancy and childhood. Genetic factors are implicated in the etiology of epilepsy. A familial susceptibility to seizures have been recognized but the exact mode of inheritance remains unclear. The chief objective was to determine the inheritance pattern and to correlate its prevalence among closer relatives on the basis of sex, degree of relationship and age of onset of the disease. Materials and methods: A pedigree analysis of 100 clinically diagnosed children with idiopathic epilepsy seen between 1994 and 1997 at the Paediatric Neurology Clinic of Government Medical College, Thiruvananthapuram was done. The mode of inheritance was tested according to the genetic hypothesis of segregation analysis. Results: Positive family history was observed in 49% of the probands. A high proportion of probands with an early onset of disease showed involvement of family members and a significant sex predisposition for females was obtained. Relatives of female probands were affected more than those of males. Mothers were found to transmit the disease to offsprings more than the epileptic fathers. Conclusion: The results of pedigree analysis supported the hypothesis of an autosomal multifactorial mode of inheritance, with 86% heritability and a lower threshold for the disease to manifest. The application of modern genetic principles like identification of susceptibility gene to epilepsy, linkage and association studies would advance our understanding of the etiology of seizure disorders. Genetic factors may play a major role in the predisposition of relatives to epilepsy in families of probands with idiopathic epilepsy. The present study may aid in the genetic counselling of parents with epilepsy.

Microduplications At 22q11.21 are Associated with Classic Bladder Exstrophy

Purpose Classic exstrophy of the bladder (CBE) is part of the exstrophy-epispadias complex (EEC), a spectrum of urogenital anomalies in which part or all of the distal urinary tract fails to close. Familial occurrence has been observed, and previous studies have suggested an underlying multifactorial mode of inheritance. To date, no causative genetic or non-genetic factor has been unequivocally identified in humans. The present study aimed to identify microaberrations characterized by loss or gain of genomic material that contribute to the EEC at a genome-wide level. Material and Methods Molecular karyotyping, utilizing 549,839 single nucleotide polymorphisms (SNPs) with an average spacing of 5.7 kilobases, was performed to screen an initial cohort of 16 EEC patients. Results A de novo microduplication involving chromosomal region 22q11.21 was identified in one CBE patient. Subsequent multiplex ligation-dependent probe amplification (MLPA) analysis was performed in a further 50 EEC cases. One patient with an overlapping 22q11.21 duplication was identified in whom the duplication had been transmitted from the unaffected mother. Conclusions Chromosomal region 22q11 is well known for its susceptibility to genomic rearrangements, and these are associated with various syndromes including the velo-cardio-facial/DiGeorge syndrome (VCFS/DGS), the der(22) syndrome, and the cat-eye syndrome. Duplications in this region result in a wide and variable spectrum of clinical presentations including features of the VCFS/DGS, while some carriers present with a completely normal phenotype.Our findings extent the phenotypic spectrum of the 22q11.2 duplication syndrome, and indicate that this aberration predisposes to CBE with incomplete penetrance.

Genome-Wide Linkage Scan in a Moroccan Family With Autosomal-Recessive Exstrophy of the Bladder Identifies a Novel Susceptibility Locus on Chromosome 3p25.3

Purpose Exstrophy of the bladder (EB) is part of the bladder exstrophy-epispadias complex (BEEC) representing a spectrum of urogenital anomalies in which part or all of the distal urinary tract fail to close and are exposed on the outer abdominal wall. Familial occurrence is rare and previous studies are suggestive of an underlying multifactorial mode of inheritance. However, no causally related genetic or non-genetic factor has been identified so far. In this study, we aim to identify potential risk/modifying loci that might contribute to EB. Material and Methods A genome-wide linkage scan was performed in a consanguineous kindred of Moroccan origin where three affected males showed the same phenotype of classic EB. Results Strongest evidence for linkage was obtained for chromosomal region 3p25.3 (parametric LOD score of 3.4). This region comprises at least seven genes listed in the current NCBI map (Build 36.1) and sequence analysis of all these genes has been initiated. Conclusions Our data provide a basis for the localization and identification of a causally related gene implicated in EB, most likely localized on 3p25.3.

GENETICS OF SCOLIOSIS

Scoliosis is one of the oldest known deformities of humankind; however, the cause still remains ill defined. Although there is a lack of uniform agreement on the inclusion criteria for the definition of scoliosis, most investigators agree that a coronal curve must measure at least 10 degrees for the patient to be considered to have scoliosis. A broad range of articles were reviewed and the relevant publications that contributed information regarding the genetics of scoliosis were selected for inclusion in this report. Based on family pedigree and genetic studies, the proposed pattern of inheritance for markers of scoliosis are expected to be autosomal dominant, X-linked, multigene, or multifactorial. This is further complicated by locus heterogeneity, allele heterogeneity, and carrier states found in normal individuals. Although none of these modes of inheritance has been definitively proven, it appears that a multifactorial mode of inheritance with variable penetrance is the most likely method.

Genetics of psoriasis

AbstractPsoriasis is a chronic inflammatory disease of unknown cause with variable clinical expression. In the absence of clearly identified psoriasis autoantigen, there is debate as to whether it can be considered an autoimmune disease. However, considerable evidence obtained from twin studies, demographic studies, and genome‐wide scans performed in several extended patient cohorts and carefully selected psoriasis pedigrees, clearly established that genetics is a key component in the development of psoriasis. The common thought is that psoriasis has a multifactorial mode of inheritance, and that in order for an individual to develop clinical lesions, several psoriasis‐susceptibility genes have to interact together and with various environmental factors. This article reviews some past and current findings on the genetics of psoriasis.

Bladder exstrophy–epispadias complex: Investigation of suppressor of variegation, enhancer of zeste and Trithorax (SET) as a candidate gene in a large cohort of patients

The bladder exstrophy-epispadias complex (BEEC) describes a rare anterior midline defect with variable expression involving the infra-umbilical abdominal wall, including the pelvis, urinary tract and external genitalia. It is assumed that the underlying cause of BEEC is a multifactorial mode of inheritance; however, its aetiology remains unknown. Only a few BEEC patients with distinctive cytogenetic features such as numeric or structural chromosomal abnormalities have been reported. The observation of translocations concerning the region of chromosome 9q32-q34.1 in two patients implies that this region bears a candidate gene which, during early blastogenesis, governs the development of this primary field. In this context, we considered the suppressor of variegation, enhancer of zeste and Trithorax (SET) gene, located at chromosome 9q34, to be a good candidate, as the protein encoded is involved in the regulation of cell proliferation and differentiation. Moreover, SET expression was detected in embryonic kidney. A total of 33 patients affected with BEEC were analysed for mutations in the SET gene. SET analysis did not reveal either a mutation or the presence of four single-nucleotide polymorphisms (dbSNP124) already described in the database. The data obtained in this study most likely exclude the SET gene as a possible genetic cause of BEEC. Hence, other genes in this region may contribute to the development of this midline defect.

Genetic and molecular biological aspects of the bladder exstrophy-epispadias complex (BEEC)

The bladder exstrophy and epispadias complex (BEEC) is an anterior midline defect with variable expression involving the infraumbilical abdominal wall including the pelvis, urinary tract, and external genitalia. The incidence varies with regard to ethnical background, sex, and phenotypic expression, and an incidence of 1:20,000 to 1:80,000 has been observed in the middle European population. No gene defect has been attributed to BEEC thus far and chromosomal aberrations or genetic syndromes associated with BEEC have only rarely been reported. According to epidemiological data, a complex genetic as well as a multifactorial mode of inheritance could underlie BEEC. However, no single teratogenic agent or environmental factor has been identified, which could play a dominant role in the expression of the BEEC.A risk of recurrence of 0.5-3% has been described in families with one affected subject. These values correspond to an increased recurrence risk estimated to be as high as 200- to 800-fold when compared to the common population. Due to the paucity of affected sib pairs and suitable multiplex families, conventional linkage analysis to identify candidate genes causally related with BEEC appears to be unfeasible. Large association studies and consecutive linkage disequilibrium mapping should therefore lead to the identification of candidate genes. Also new methods including matrix-based comparative genomic hybridization (CGH) are promising and have successfully been used in the past (e.g., CHARGE association). Moreover, the low incidence of the BEEC requires close cooperation between clinicians in the operative and nonoperative specialties as well as geneticists for successful gene search.

A PEDIGREE OF ONE FAMILY WITH DELAYED SLEEP PHASE SYNDROME

The prevalence of delayed sleep phase syndrome (DSPS) has been estimated to be quite low. Although no genetic inheritance pattern has been described, it has been reported that close to 50% of DSPS patients have biological relatives with similar symptoms. A pedigree of one extended family with symptoms suggestive of DSPS has been identified. Morningnesseveningness questionnaires were administered to all first- and second-degree relatives of a proband identified with DSPS. A total of 51 (86%) questionnaires were returned, and 6 adult biological relatives of 27 (22%) showed a preference for eveningness, which is much higher than reported in the general population. Both the paternal and maternal branches contained affected individuals, suggesting the possibility of a bilineal mode of inheritance. While the trait did not obey simple Mendelian inheritance, the vertical patterns of transmission were consistent with either an autosomal dominant mode of inheritance with incomplete penetrance or a multifactorial mode of inheritance. These data provide some preliminary support to the notion that eveningness, and thus DSPS, may have a genetic component. The prevalence of symptoms suggestive of DSPS is higher in this family than reported in the general population. Case reports such as this support the utility of larger, more systematic studies. It is unclear whether this degree of familiarity is representative of that in the general population. (Chronobiology International, 18(5), 831–840, 2001)

Exfoliation syndrome: Clinical and genetic features

We have ascertained a large number of individuals and families with exfoliation syndrome in order to clarify the disorder’s mode of inheritance. Patients with exfoliation syndrome and their relatives were recruited from the practices of a group of ophthalmologists in Maritime Canada. The degree to which the subjects were affected was graded according to a standardized 1–4-point clinical scheme. Pedigrees were constructed from information supplied by family members and from genealogical sources. A total of 782 patients and relatives participated, of whom 467 were definitely affected. The mean age of affected males and females did not differ significantly, but females appeared to be more severely affected at ascertainment than males. More than half of the affected subjects had definite exfoliation in only one eye. Approximately 30 multiplex families were discovered, including one containing 23 affected members among a total of 137 examined individuals that constitutes the largest exfoliative pedigree thus far described. We observed well-documented paternal transmission of the trait, a finding that has not to our knowledge been previously reported. Clustering of cases in the families provides evidence for the involvement of genetic factors. The possibility of homozygosity is suggested in a few patients by the earlier or more frequent presentation of the disorder in the offspring of two affected parents or consanguineous pairings. Although a multifactorial mode of inheritance cannot be excluded, exfoliation syndrome appears to be inherited as an autosomal dominant trait whose late onset and incomplete penetrance poses a significant but not insuperable obstacle to pedigree construction.

Recurrence risk figures for isolated tetralogy of Fallot after screening for 22q11 microdeletion.

Isolated tetralogy of Fallot (TF) has a multifactorial mode of inheritance in most cases, and recurrence risk rates of 2.5-3% have been attributed to first degree relatives of an affected...

Influence of stochastic events on the phenotypic variation of common white leg markings in the Arabian horse: implications for various genetic disorders in humans.

One method of assessing the influence of stochastic events on phenotypic variation is to study morphological differences in paired limbs of the same individual. These limbs have identical genotypes and similar intra-uterine environments and are analogous to monozygotic twins. Common white leg markings have a multifactorial mode of inheritance in the Arabian horse. Asymmetry occurs frequently for these markings. Using computerized registration records obtained from the Arabian Horse Registry of America, Inc., the types of markings were quantified in the left foreleg and left hind leg of bay and chestnut horses when a specific marking occurred in (1) a paired right leg, (2) both right legs, and (3) both right legs and the other left leg. The variation in the markings in the left legs of these horses is evidence of the role of stochastic events during development. The relatively high frequency of a specific type of asymmetry, with one leg being completely pigmented, is of special biological interest and has implications for various human disorders that are characterized by reduced penetrance and variable expressivity.

Further evidence that a mouse Chromosome 4 locus influences cerebellar folial pattern

The cerebellar folial pattern of mice displays marks variation amomng inbred strains. Previous studies of progeny of crosses of C57BL/6 mice with DBA/2J and BALB/cByJ mice indicated a multifactorial mode of inheritance in both cases. The cross with DBA/2J led to the mapping, to Chromosome 4, of a locus ( Cfp-1) that influences the frequency of the intraculminate fissure. Here we report that Cfp-1) influences the frequency of the declival sulcus and appears to influence the frequency of the intraculmiate and precentral fissures, in F 2 hybrid offspring from crosses of C57BL/6J and BALB/cByJ mice.

Some genetic aspects of the epilepsies: Waking and sleep EEGs in siblings of patients with various idiopathic and symptomatic seizure types

Waking and sleep EEGs were recorded in siblings of patients with various idiopathic and symptomatic seizure types. More than one-third of the siblings of nearly all seizure types showed epileptic activity (EA). The lowest rate of EA was found in siblings of patients with complex partial seizures (24.1%), the highest in those of patients with idiopathic absences (72%). More EA was found in siblings of patients with idiopathic absences (72%) than in those of patients with symptomatic absences (46.7%). On the other hand, the siblings of patients with idiopathic generalized tonic-clonic seizures (42%) showed the same rate of EA as those of patients with symptomatic tonic-clonic seizures (41%). By counting the EA, however, considerably more EA was found in siblings of patients with the idiopathic type (one paroxysm every 53 s) than in those of patients with the symptomatic type (one paroxysm every 229.3 s). One-quarter to one-half of the EA was recorded exclusively in sleep. Predominantly generalized spike-and-wave complexes were seen in siblings of all seizure types. Benign sharp wave foci were recorded in 1.5–5.8% of siblings of patients of nearly all seizure types, most frequently (5.8%) in those of patients with rolandic epilepsy. Photosensitivity was also found in siblings of patients of nearly all seizure types, most often in those of patients with absences (22.5%). The highest rates of EA were recorded in siblings of patients of all seizure types in the waking EEG during hyperventilation, during sleep in Stage C. The most EA was seen in siblings of nearly all seizure types in the age range between 6 and 15 years. Significantly more EA was recorded in siblings of female patients with Lennox-Gastaut syndrome (66.7%:33.3%), in those of patients with febrile seizures (68.5%:43.3%), as well as complex partial seizures (55.6%:20%). More EA was also seen in female siblings of patients with symptomatic generalized tonic-clonic seizures (54.5%:30%) and complex partial seizures (27.8%: 18.2%). A multifactorial mode of inheritance is supposed.

Common White Facial Markings in Bay and Chestnut Arabian Horses and Their Hybrids

Common white facial and leg markings have a multifactorial mode of inheritance in Equus caballus. Evidence for the complexity of the genetic component is the observation that chestnut (e/e) horses have more extensive white markings than do bay (E/-) horses. Computerized records obtained from the Arabian Horse Registry of America, Inc., were used to determine if heterozygous (E/e) bay horses have more extensive white facial markings than do homozygous (E/E) bay horses. Thirty-five sire families were analyzed. Each sire family consists of a sire, his foals, and the dams of those foals. The facial region was divided into five areas, and each horse was given a score from 0 to 5 according to the number of areas with whiteness. Since dams and foals with E/E genotypes cannot be identified in these sire families, mean facial scores were compared in dams and foals that were E/e and E/-. It was assumed that if a difference exists between E/e and E/E horses, the presence of E/E horses in the E/- group would reduce the mean of the E/- group. The results show that Arabian horses with the genotype E/e have more white markings than do horses with the genotype E/-, leading to the conclusion that horses with the genotypes e/e, E/e, and E/E vary as to the quantitative expression of white facial markings, with heterozygotes having an intermediate expression.

Multifactorial Inheritance of Common White Markings in the Arabian Horse

The results of a previous study were compatible with the hypothesis that common white facial markings in the Arabian horse have a multifactorial mode of inheritance. I expanded that study to (1) include the legs and therefore obtain insight into the heritability of common white markings in all peripheral regions (face and legs) of the Arabian horse and (2) investigate the influence of sex and the genotypes that produce the bay and chestnut phenotypes on the variation in common white markings. Both studies were based on computerized data obtained from the Arabian Horse Registry of America, Inc. Each leg of a horse was scored from 0 to 5 depending on the amount of whiteness present, and the four leg scores were added to obtain the total leg score for each horse. The facial region was divided into five areas, and each horse was given a score from 0 to 5 according to the number of areas with whiteness. Sire families were analyzed in which each sire family consisted of a sire, his foals, and the dams of those foals. There was a correlation between white facial scores and white leg scores, suggesting that both types of white markings are influenced by the same genetic mechanism. Sire-foal and dam-foal regression analyses were compatible with the hypothesis that common white leg markings also show multifactorial inheritance. Although the results support the model that additively acting genes (polygenes) influence the presence and extent of common white markings, the results also show that males are slightly more marked than are females and that chestnut horses are more heavily marked than are bay horses.(ABSTRACT TRUNCATED AT 250 WORDS)