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PubMed1980

Metabolic interference and the + - heterozygote. a hypothetical form of simple inheritance which is neither dominant nor recessive.

Another form of simple inheritance is possible which is neither dominant nor recessive and in which the heterozygote alone is affected. In this system, homozygosity for the normal allele AA, and the mutant allele A'A', give a normal phenotype. Only the heterozygous condition AA' (+ - heterozygote) produces an abnormal phenotype because the two alleles, when present together, interact to produce a harmful effect. This metabolic interference may occur because the two allelic genes code for different subunits of a multisubunit enzyme or structural protein. The two genes may interact in other ways and need not be allelic. The various matings result in pedigrees, which in some cases resemble those of dominant or recessive inheritance, and in other cases are unique. Certain unusual pedigrees in the literature are compatible with the predictions of metabolic interference and are difficult to explain by other means. Metabolic interference is most likely to be recognized as: (1) a disorder limited to females, apparently dominant or recessive, especially a disorder passed to affected females through unaffected males; (2) a disorder occurring in all members of a large sibship with normal parents; (3) a disorder occurring in all members of a large sibship with one parent similarly affected; (4) an apparently dominant disorder with females more severely affected than males; (5) an apparently X-linked dominant disorder in which males are not more severely affected; or (6) any autosomal dominant disorder. Examples of possible metabolic interference exist among disorders of animals, and the mechanism could be a factor in speciation. Tissue culture methods could be used to demonstrate metabolic interference.

Alleles↗
PubMed1981

[Effect of the dynamic factors of space flight on the mutagenic effect of radiation. II. Development of recessive lethals and loss of X-chromosomes in Drosophila melanogaster oocytes].

The modifying effect of dynamic space-flight factors on radiation damage of Drosophila oocytes was measured by the frequencies of X-chromosomal non-disjunction, loss and sex-linked recessive lethals. It has been shown that with a slight increase in the non-disjunction frequency, dynamic factors did not influence the frequency of loss events in irradiated oocytes. The yield of recessive lethal mutations increased in irradiated oocytes-7 both upon pre- and postradiation action of dynamic factors. A similar increase in the frequency of recessive lethals was observed after an additional action of acceleration on irradiated oocytes. It is assumed that the modifying effect of dynamic factors is associated with repair repression at early stages of radiation damage.

Acceleration↗
PubMed1983

[Role of recessive lethal genes in spontaneous embryonal lethality in random-bred rat and mouse populations in Cuba].

Spontaneous embryonic lethality and the recessive lethal gene frequency in the gene pool of noninbred mice and rats of the bioteria of the National Research Center of the Cuba Republic Academy of Sciences were investigated. It was established that the level of spontaneous embryonic lethality among mice increased greatly as compared to that in 1977 and was 40% (versus 20% in 1977). Of this number, 30% falls within the postimplantation period. In noninbred rats, these values constituted 21.4 and 8.1%, respectively. High embryonic lethality among noninbred mice may be determined by genetic causes and the influence of ecological factors. The frequency of recessive lethals among noninbred mice was 28%, that among rats 20.8%. It is characteristic that in both categories, recessive lethals became apparent only in the postimplantation period of embryogenesis.

Animals↗
PubMed1995

Recessive mutations in the second largest subunit of TFIIIC suggest a new step in RNA polymerase III transcription.

An analysis of mutant S. cerevisiae strains selected for their ability to increase transcription by RNA polymerase (pol) III has identified 14 isolates in which this phenotype is recessive. Genetic linkage and complementation studies suggest that all 14 isolates contain recessive alleles of PCF1. PCF1 encodes the 131-kDa subunit of transcription factor IIIC (TFIIIC131) and was identified previously by dominant mutations that also increased transcription by pol III. The recessive mutation, pcf1-3, results in a conservative substitution (R728-->K) towards the carboxyl-terminus of the protein. This position is distinct from the site of the dominant mutation PCF1-1 (H190-->Y), which maps to a tetratricopeptide repeat (TPR). Site-directed mutagenesis at amino acid 728 generated one allele, pcf1-4, with a stronger phenotype than pcf1-3. Extracts from pcf1-3 and pcf1-4 strains increase pol III transcription two- to threefold and ninefold, respectively, over wild-type under conditions that permit either single or multiple rounds of initiation. The entire effect of these mutations in vitro can be accounted for by an increase in the amount of transcriptionally active TFIIIB. In contrast, PCF1-1 primarily affects the rate of preinitiation complex assembly. The genetic, molecular, and biochemical data suggest that amino acid 728 in TFIIIC131 constitutes part of a structural domain in this protein that affects TFIIIB activity by influencing a previously undefined step in transcription. This step is suggested to occur after the recruitment of TFIIIB to DNA.

Alleles↗
PubMed1995

The histology of new attachment utilizing a thick autogenous soft tissue graft in an area of deep recession: a case report.

An area of deep, long-standing recession on a mandibular first premolar was treated for root coverage in a 40-year-old woman. The recession was 6.0 mm deep with a probing depth of 2.0 mm, and there was no attached gingiva. A thick (1.5-mm) free autogenous epithelium and connective tissue graft from the palate was placed to the cementoenamel junction of the tooth after instrumentation and tetracycline conditioning of the root surface. The tooth and facial soft tissues were removed in block section 10.5 months later. At the time of extraction, there had been a gain of 5.0 mm of root coverage, and there was 5.0 mm of keratinized gingiva on the facial aspect. The probing depth was 1 mm. Histologic measurement showed 4.4 mm of new attachment and 4.0 mm of new bone growth. The coronal extent of the new attachment and new bone were in an area previously exposed by recession.

Adult↗
PubMed1995

Resorbable membrane in the treatment of human buccal recession: a nine-case report.

Recent studies have reported the successful use of guided tissue regeneration procedures with nonresorbable barrier membranes to treat buccal recession in humans. Nonresorbable membranes, however, require a reentry procedure for removal, disturbing the delicate healing process. Resorbable membranes were used in a guided tissue regeneration procedure in nine patients with one site of buccal recession each. The resorbable barrier yielded satisfactory clinical results, providing significant gains in probing attachment and root coverage. However, both the surgical technique and the design of the barrier used require improvement for application at sites of buccal recession.

Adult↗
PubMed1993

Guided tissue regeneration and a free gingival graft for the management of buccal recession: a case report.

Five patients with buccal gingival recession (4 to 6 mm) underwent surgical treatment consisting of a guided tissue regeneration procedure associated with a free gingival graft. The graft was used to cover the newly formed tissue on the root surface at the reentry. Root coverage was complete in three patients, while 1 mm of recession remained in the other two patients. The free gingival graft reconstructed the keratinized tissue, which had been lost because of recession. Moreover, it allowed the mucogingival junction, which had been displaced coronally during the first surgery, to be realigned, therefore preventing a shallowing of the vestibule.

Adult↗
PubMed1997

Autosomal recessive Sorsby fundus dystrophy revisited: molecular evidence for dominant inheritance.

Sorsby fundus dystrophy (SFD) originally was characterized as an autosomal dominant disorder in which patients lose central vision during the 4th or 5th decade of life. Since Sorsby's initial description, interfamilial phenotypic variations have been noted and have given rise to controversy as to whether SFD constitutes more than one nosologic entity. In addition, several reports have proposed the existence of a recessively inherited form of SFD. The recent identification of the tissue inhibitor of metalloproteinases-3 (TIMP3) as the disease-causing gene in SFD has made it possible to address the questions of clinical and genetic heterogeneity. In this study, we reinvestigated a large, highly consanguineous Finnish family previously diagnosed as having early-onset autosomal recessive SFD. We identified a novel heterozygous Gly166Cys mutation in TIMP3 in all affected individuals and provide strong evidence for an autosomal dominant inheritance of the SFD phenotype in this family. Our results, in conjunction with a critical review of the reported cases, render the existence of a recessive mode of inheritance in SFD questionable. Considering all available data, we suggest that SFD is a genetically homogeneous, autosomal dominant condition.

Adult↗
PubMed1997

Strategies for mapping heterogeneous recessive traits by allele-sharing methods.

We investigate strategies for detecting linkage of recessive and partially recessive traits, using sibling pairs and inbred individuals. We assume that a genomewide search is being conducted and that locus heterogeneity of the trait is likely. For sibling pairs, we evaluate the efficiency of different statistics under the assumption that one does not know the true degree of recessiveness of the trait. We recommend a sibling-pair statistic that is a linear compromise between two previously suggested statistics. We also compare the power of sibling pairs to that of more distant relatives, such as cousins. For inbred individuals, we evaluate the power of offspring of different types of matings and compare them to sibling pairs. Over a broad range of trait etiologies, sibling pairs are more powerful than inbred individuals, but for traits caused by very rare alleles, particularly in the case of heterogeneity, inbred individuals can be much more powerful. The models we develop can also be used to examine specific situations other than those we look at. We present this analysis in the idealized context of a dense set of highly polymorphic markers. In general, incorporation of real-world complexities makes inbred individuals, particularly offspring of distant relatives, look slightly less useful than our results imply.

Chromosome Mapping↗
PubMed1997

Combined use of root conditioning, fibrin-fibronectin system and a collagen membrane to treat a localized gingival recession: a 10-case report.

The purpose of this research was to evaluate the effectiveness of combined root surface conditioning with tetracycline HCI, fibrin sealing system, guided tissue regeneration procedure and coronal sliding flap application in the treatment of localized gingival recessions. The present study was conducted on 10 patients with localized facial recessions of at least 3mm. A trapezium-shaped flap was elevated apically to the margin of the bone dehiscence and the root surface was thoroughly scaled by hand instruments and burs. Tetracycline HCI (pH 1.9) solution was then topically applied for 5 minutes and the root surface thoroughly rinsed with sterile saline. A collagen membrane was trimmed and shaped to cover the entire root surface and later removed and a fibrin sealing system injected onto the root surface. Immediately membrane was placed again on the root surface without applying any pressure. The flap was sutured in the coronal position to completely cover the root surface and membrane. Control group patients were treated with only coronal sliding flap operation. Sutures were removed 10 days after surgery. Patients were clinically reevaluated 6 months postoperatively. The mean amount of root surface coverage obtained was similar in the test and control groups (test = 71.7%; control = 68.55%) but the clinical attachment gain (test = 4.21mm; control = 2.86mm) and pocket depth variations (test = 1.14mm reduction; control = 0.07mm reduction) differed significantly (P < 0.001). This study found promising healing of localized gingival recessions to result from a combined use of tetracycline HCI root demineralization, fibrin sealing system application, guided tissue regeneration procedure and coronal sliding flap operation.

Administration, Topical↗
PubMed1998

High incidence of autosomal recessive nonsyndromal congenital retinal nonattachment (NCRNA) in an Iranian founding population.

In an isolated and founding Iranian population the prevalence of congenital total blindness is 1.1%. Clinical findings such as lack of perception of light, massive retrolental mass, shallow anterior chamber and nystagmus, in otherwise normal individuals, correspond to nonsyndromal congenital retinal nonattachment. To determine the inheritance of this disease we constructed an extensive nine-generation pedigree of the affected kindred living in the Iranian founding population. The pedigree, which includes 42 patients from 25 sibships, clearly suggests autosomal recessive inheritance. To verify the inheritance, we compared the average coefficient of inbreeding (F) of the affected sibships with that of the control sibships, calculated the patients' sex ratio, and also compared the observed relative frequency of the disease with its expected relative frequencies for different modes of inheritance. The patients' average F value is significantly greater than that of the controls (P < 0.001). The sex ratio of the patients is close to unity and the observed relative frequency of the disease is close to that of an autosomal recessive trait. All these findings strongly support autosomal recessive transmission of this disease.

Adolescent↗
PubMed1989

Autosomal recessive epidermolysis bullosa simplex. Generalized phenotypic features suggestive of junctional or dystrophic epidermolysis bullosa, and association with neuromuscular diseases.

With few exceptions, epidermolysis bullosa (EB) simplex is an autosomal dominant disorder characterized by rather localized and recurrent nonscarring blister formation; mucous membranes and other organs are usually uninvolved. Recently, two patients were described with an autosomal recessive form of EB simplex associated with muscular dystrophy. We now describe four additional patients with autosomal recessive EB simplex, three of whom had associated muscular dystrophy or congenital myasthenia gravis. These patients had generalized cutaneous findings, including milia, atrophic scarring, nail dystrophy, and scalp alopecia, which have been classically attributed to either junctional or dystrophic EB. Each patient had significant oral cavity involvement, and in two, marked growth retardation and anemia were also present. Our findings suggest that autosomal recessive EB simplex may be characterized by rather severe cutaneous and extracutaneous disease activity, and may be associated with at least two distinct neuromuscular diseases.

Adult↗
PubMed2001

Recessive ataxia with ocular apraxia: review of 22 Portuguese patients.

BACKGROUND: The recessive ataxias are a heterogeneous group of neurodegenerative disorders characterized by cerebellar ataxia associated with a number of different neurologic, ophthalmologic, or general signs. They are often difficult to classify in clinical terms, except for Friedreich ataxia, ataxia-telangiectasia, and a relatively small group of rare conditions for which the molecular basis has already been defined. OBJECTIVES: To study the clinical presentation and to define diagnostic criteria in a group of Portuguese patients with ataxia and ocular apraxia, an autosomal recessive form without the essential clinical and laboratory features of ataxia-telangiectasia. PATIENTS AND METHODS: We reviewed 22 patients in 11 kindreds, identified through a systematic survey of hereditary ataxias being conducted in Portugal. RESULTS: Age at onset ranged from 1 to 15 years, with a mean of 4.7 years. The duration of symptoms at the time of last examination varied from 5 to 58 years. All patients presented with progressive cerebellar ataxia, the characteristic ocular apraxia, and a peripheral neuropathy. Associated neurologic signs included dystonia, scoliosis, and pes cavus. Magnetic resonance imaging was performed in 16 patients, all of whom showed cerebellar atrophy. CONCLUSIONS: Ataxia with ocular apraxia may be more frequent than postulated before, and may be identified clinically using the following criteria: (1) autosomal recessive transmission; (2) early onset (for most patients in early childhood); (3) combination of cerebellar ataxia, ocular apraxia, and early areflexia, with later appearance of the full picture of peripheral neuropathy; (4) absence of mental retardation, telangiectasia, and immunodeficiency; and (5) the possibility of a long survival, although with severe motor handicap.

Adolescent↗
PubMed1998

Arrestin gene mutations in autosomal recessive retinitis pigmentosa.

OBJECTIVE: To assess the clinical and molecular genetic studies of patients with autosomal recessive retinitis pigmentosa associated with a mutation in the arrestin gene. DESIGN: Results of molecular genetic screening and case reports with DNA analysis and clinical features. SETTING: University medical center. PATIENTS: One hundred twenty anamnestically unrelated patients with autosomal recessive retinitis pigmentosa. METHODS: DNA analysis was performed by single strand conformation polymorphism followed by nucleotide sequencing to search for a mutation in exon 11 of the arrestin gene. Clinical features were characterized by visual acuity slitlamp biomicroscopy, fundus examinations, fluorescein angiography, kinetic visual field testing, and electroretinography. RESULTS: We identified 3 unrelated patients with retinitis pigmentosa associated with a homozygous 1-base-pair deletion mutation in codon 309 of the arrestin gene designated as 1147delA. All 3 patients showed pigmentary retinal degeneration in the midperipheral area with or without macular involvement. Patient 1 had a sibling with Oguchi disease associated with the same mutation. Patient 2 demonstrated pigmentary retinal degeneration associated with a golden-yellow reflex in the peripheral fundus. Patients 1 and 3 showed features of retinitis pigmentosa without the golden-yellow fundus reflex. CONCLUSIONS: Although the arrestin 1147delA has been known as a frequent cause of Oguchi disease, this mutation also may be related to the pathogenesis of autosomal recessive retinitis pigmentosa. This phenomenon may provide evidence of variable expressivity of the mutation in the arrestin gene.

Adult↗
PubMed1976

Unilateral medial rectus recession for small-angle esotropia.

Ten patients with small-angle esotropia of 18 prism diopters or less were treated with a unilateral medial rectus recession of 5 mm. Nine of the ten cases considerably improved; one showed only minimal improvement. There were no overcorrections, but two cases did show lateral incomitance with a greater correction on gaze in the field of action of the recessed medial rectus muscle. Two patients became monofixators after the surgery. These had been patients with accommodative esotropia who had decompensated and had surgery for the nonaccommodative portion of the total esotropia. When indicated, the recession of one medial rectus muscle is a safe and predictable procedure for small-angle esotropia. An average correction of 11.6 prism diopters was obtained at distance and one of 11.3 prism diopters at near.

Adolescent↗
PubMed1977

Adjustable rectus muscle recession surgery. A follow-up study.

Fifty-six patients underwent an adjustable rectus muscle recession procedure. This procedure permits the surgeon to enhance or diminish the amount of muscle recession on the evening after surgery or the first postoperative day if cover-testing indicates an inappropriate amount of undercorrection or overcorrection. The adjustable rectus muscle recession technique seems to be a practical and effective means to change the strabismic deviation postoperatively. The procedure requires patient cooperation and is most suitable for patients age 15 years and older. The procedure has been effective in altering the angle of deviation, and this alteration has been stable during the follow-up period in most cases. In this initial series, the reoperation rate was low, postoperative alignment was excellent, and complications were minimal.

Adolescent↗
PubMed1992

A surgical procedure to minimize lower-eyelid retraction with inferior rectus recession.

Advancement of the capsulopalpebral head at the time of inferior rectus recession has been described as a technique to minimize postoperative lower-eyelid retraction. In a prospective randomized masked clinical trial, this technique combined with inferior rectus recession was compared with inferior rectus recession alone, with respect to post-operative lower-eyelid retraction. The mean (+/- SD) postoperative lower-eyelid retraction was 0.7 +/- .82 mm for patients in whom the capsulopalpebral head was advanced, as opposed to 1.3 +/- .85 mm for the control group. This difference was statistically significant (Student's t = 2.787; P = .006).

Eyelids↗
PubMed1996

Adjustable suture technique for levator recession.

OBJECTIVE: To determine whether an adjustable suture technique is clinically useful in levator recession surgery. DESIGN: Consecutive clinical series. SETTING: Inpatient hospital and ambulatory surgical center. PARTICIPANTS: Ten patients who were undergoing levator recession surgical procedures for correction of eyelid retraction constituted the group of subjects of this study. OUTCOME MEASURES: Outcome measures included margin-reflex distance and palpebral fissure measurements. RESULTS: Postoperative margin-reflex distance and palpebral fissure measurements were within 0.5 mm of the desired eyelid position in 10 or 14 procedures and within 1 mm of the desired position in 12 of 14 procedures. CONCLUSION: Adjustable sutures may be a useful adjunct in levator recession surgery.

Adult↗