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A family is described in which knuckle pads, leukonychia, deafness, and keratosis palmoplantaris are present as a syndrome is several members. This is the second such family reported demonstrating that keratosis palmoplantaris is part of the syndrome. Inheritance pattern is probably autosomal dominant.
Recent studies of Mendelian disease have begun to clarify the clinical spectrum of the group of disorders that make up familial, focal segmental glomerulosclerosis (FSGS) and nephrotic syndromes. In familial forms of focal segmental glomerulosclerosis (FSGS), both autosomal recessive and dominant inheritance patterns have been reported. At least three genes have been identified which, when defective, cause familial FSGS or nephrosis: the NPHS1 gene, encoding nephrin; the NPHS2 gene, encoding podocin; and the ACTN4 gene, encoding a-actinin-4. Because the majority of FSGS cases occur as sporadic disease, the recently described mutations in the NPHS2 gene "in approximately 25 percent of cases of apparently sporadic, steroid-resistant FSGS in children" have claimed great interest. The applicability of these observations to adults, including the possible importance of the nephrin and alpha-actinin-4 genes in the sporadic disease, remain to be determined. Finally, the mechanisms of podocyte damage and the molecular basis of glomerulosclerosis are reviewed.
CONTEXT: Mutations in cystic fibrosis transmembrane conductance regulator (CFTR), in cationic trypsinogen (PRSS1) and in serine protease inhibitor Kazal type 1 (SPINK1) genes have been associated with chronic pancreatitis (alcohol related, idiopathic and hereditary). However, the inheritance pattern is still not clear. PATIENTS: Eighty-two unrelated Brazilian patients with chronic pancreatitis (alcohol-related disease in 64, idiopathic disease in 16, and hereditary disease in 2). Two hundred unrelated individuals with an ethnic distribution comparable to the patients were studied as controls. MAIN OUTCOME MEASURE: Detection of mutations in CFTR, PRSS1, and SPINK1 genes. RESULTS: Mutations in the CFTR gene were found in 8 patients (9.8%) with chronic pancreatitis, 5 of them with idiopathic disease. Interestingly, the only clinical symptom in a male patient in the alcoholic group, who was a compound heterozygote (DeltaF508/R170C) for two CFTR mutations, was pancreatitis without infertility or pulmonary involvement. In the PRSS1 gene, the E79K change in exon 3 was found in one patient (1.2%) with alcohol-related chronic pancreatitis. Four different alterations were identified in the SPINK1 gene. CONCLUSIONS: Mutations in the CFTR gene represent the major cause of idiopathic chronic pancreatitis in Brazilian patients. No mutation was found in the PRSS1 gene among our patients suggesting further genetic heterogeneity for hereditary and idiopathic chronic pancreatitis. Interestingly, the most frequent SPINK1 N34S mutation was not present in patients or controls. Moreover, the -253C allele for the SPINK1 gene was significantly more frequent in patients than controls (P=0.004), suggesting that it might represent a risk factor for the development of pancreatitis in our population.
Sperm cells within pollen grains and pollen tubes of alfalfa (Medicago sativa L.) were observed at the ultrastructural level, and their plastid DNA was detected by DAPI (4,6-diamidino-2-phenylindole) staining. One sperm pair within the pollen grain and three sperm pairs within pollen tubes were reconstructed in three-dimensions from serial ultrathin sections. The two sperm cells are linked by cytoplasmic bridges in both pollen grains and tubes, and the vegetative nucleus is closely associated with the sperm cells within the pollen tube. The number of plastids and plastid nucleoids (DNA aggregates) in the sperm cell pair, collectively, is not significantly different from that in the generative cell; however, over 60% of the sperm cell plastids contain no DNA detectable with DAPI. The mean number of mitochondria in sperm cells is reduced from that in the generative cell (from 54 to 17), which suggests that paternal mitochondrial inheritance probably does not occur in the genotype investigated. Sperm cells of a pair may vary in their shape within the pollen grain and tube, but the number of plastids and mitochondria is not significantly different between the sperm cells. Therefore, heterospermy is not a factor determining cytoplasmic inheritance patterns in this species.
Leydig cell hypoplasia(LCH) or agenesis, which has an autosomal recessive inheritance pattern, is a well defined form of male pseudohermaphroditism resulting from inadequate fetal testicular Leydig cell differentiation. These patients exhibit a wide clinical spectrum that ranges from phenotypic females to males with micropenis, and have low levels of serum testosterone and elevated levels of LH. Recently, it has become clear that defective male sex differentiation in patients with LCH is caused by deficient LH receptor signal transduction. The fetal Leydig cells of LCH patients fail to respond to adequate levels of placental hCG, resulting in inappropriate fetal androgen production. At puberty, adult-type Leydig cells do not mature and do not produce sufficient androgen for normal secondary sex differentiation.
Total anonychia congenita is a very rare disorder in which all the finger nails and the toenails are absent without significant bone anomalies. This condition is reported to have an autosomal dominant inheritance pattern. There are a variety of syndromes or conditions associated with anonychia congenita. In this study we present a monozygotic twin with isolated anonychia congenita totals. Interestingly there is no family history of anonychia and this condition seems to be caused by a sporadic mutation.
BACKGROUND: Balkan endemic nephropathy (BEN) is a non-inflammatory, chronic, slow progressing kidney disease, frequently associated with urinary tract tumors. BEN displays familial clustering without an apparent Mendelian inheritance pattern. It has been suggested that environmental toxicants damage urothelial cells in genetically susceptible individuals, which could be the cause of BEN. The metabolism of some substrates that are mediated by glutathione S-transferases (GST), which are polymorphic enzymes, results in nephrotoxic products. To evaluate whether GST genetic heterogeneity could be involved in BEN, we launched a case-control study concerning the association of the most common polymorphic GST variants with BEN. METHODS: DNA was extracted from venous blood samples from 54 unrelated BEN patients and 104 controls inhabiting the same endemic region. GSTM1 and GSTT1 null deletions were identified simultaneously by a triplex polymerase chain reaction (PCR) procedure, and GSTP1 polymorphism was analyzed by PCR-restriction fragment length polymorphism (PCR-RFLP) using Alw261. RESULTS: Carriers of at least one GSTM1 wild type allele (wt-allele) were more prevalent among BEN patients compared to controls (chi2=7.92, p=0.005). The GSTT1 and GSTP1 genotype distributions did not demonstrate statistically significant differences between the groups. The carriers of at least one GSTM1 wt-allele among BEN patients were more prevalent in comparison with controls when the GSTM1 genotypes were combined in pairs with all GSTT1 (chi2=9.52, p=0.023) and GSTP1 (chi2=11.92, p=0.036) genotypes. The combined genotype distributions of the three GST genes studied among BEN patients and controls showed that the frequency of carriers of at least one GSTM1 wt-allele among BEN patients was higher or at least equal to the corresponding frequency among controls in all triple combinations. However, this difference did not reach statistical significance (chi2=14.06, p=0.170). CONCLUSIONS: GSTM1 wt-allele associates with BEN. The significantly lower prevalence of the GSTM1 deletion homozygotes among BEN patients suggests that individuals bearing the GSTM1 null genotype could be better protected.
AIM: Idiopathic scoliosis (IS) affects approximately 1-2% of the population and has a heritable component. It is clear that in general IS displays the features of a complex genetic disorder; however families displaying a Mendelian inheritance pattern have been described. Our aim is to identify families segregating rare, highly penetrant loci. In the case described here the disorder appears to cosegregate with a chromosomal rearrangement. METHODS AND MATERIALS: We have studied a family in which a pericentric inversion of chromosome 8 appears to cosegregate with idiopathic scoliosis in three generations. We have used fluorescent in situ hybridization (FISH) to identify cloned DNAs that span the breakpoints on the two arms of the chromosome. These clones allow the recovery of sequence information from the breakpoint region and identification of candidate genes. RESULTS: We have identified a YAC of 1190kb that spans the p arm breakpoint and from this a cosmid of 35kb that also identifies the break. We have derived DNA sequence information on this region. We have identified a BAC of 150kb that crosses the q arm breakpoint. The complete genomic DNA sequence of this BAC is being analyzed to identify candidate genes and to further localize the precise breakpoint. CONCLUSION: We have sublocalized within two small genomic regions the position of a possible locus for idiopathic scoliosis.
OBJECTIVE: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is an inherited cerebral arteriolar disease in adulthood, which is caused by NOTCH3 gene mutation. The main symptoms were migraine, cerebral stroke, later with mood disorders and dementia in Caucasian patients. Recently, the disease was also recognized in Asian patients, in whom the migraine is rarely reported. In order to give the clinical features of Chinese patients, we described the clinical symptoms in 4 CADASIL families. METHODS: CADASIL was diagnosed by the investigation of ultra-structure changes of arteriole in sural nerve and NOTCH3 gene mutation in the 4 index cases. Detailed clinical and routine laboratory examinations were performed in these 4 patients, including electrocardiography, nerve conduction velocity, serum glycogen, and serum homocysteine. Additionally, we also collected the clinical data of the other 83 family members through interviews and the available medical records. RESULTS: Of the 83 persons, 29 were classified as clinical suspected patients, who presented one or more of the disease-related neurological symptoms, such as cerebral ischemic events and the cognitive impairment. All of them showed no common risk factors for stroke, such as diabetic mellitus, hypertension, and heart disease. The clinical suspected patients distributed in every consecutive generations and involved both sexes, which was according to the autosomal dominant inherited pattern. The onset age of the disease ranged from 28 to 70-year-old and mainly between the 4th and the 5th decades. The main symptoms were recurrent episodic vertigo, with or without hemiplegia. At the same time or a little bit later, the cognitive impairment was developed in some patients. Compared with the typical presentations of the disease in European patients, none of our 29 patients showed migraine,one index case showed mild sensory disturbance in extremities. Elevated serum homocysteine level and abnormal of nerve conduction study in two index cases (3 and 4) were noticed. CONCLUSION: The onset age of the disease of our patients is similar to that of Caucasian patients. The main symptoms were stroke and dementia. Involvement of post circulation system was the main clinical feature for ischemic events in our patients. Dementia could be found in the early stage of disease. Migraine should not be regarded as a common clinical feature in our patients. The involvement of the peripheral nerves expanded the disease expression outside the central nervous system.
BACKGROUND: Childhood absence epilepsy (CAE) is one of the most frequently recognized syndromes among the idiopathic generalized epilepsies (IGEs). CAE is considered to be a genetic disease, with a possible polygenic inheritance pattern. The genes responsible for CAE have not been identified yet. The object of this study was to investigate whether or not CAE is associated with the gene encoding the gamma-aminobutyric acid (GABA) type-A receptor subunits alpha5 (GABRA5) and beta3 (GABRB3) in a Chinese population. METHODS: Five microsatellite DNA repeats, 69CA, 85CA, 155CA1, 155CA2, and A55CA1, adjoining chromosome 15q11-q13, were used as genetic markers. Both case-control study and transmission/disequilibrium tests (TDTs), as well as fluorescence-based semi-automated genotyping techniques, were used in 90 CAE patient-mother-father trios and 100 normal controls of Han ethnicity to conduct association analysis. RESULTS: The frequencies of allele 5 of 69CA, alleles 2 and 8 of 85CA, alleles 6 and 7 of 155CA1, allele 2 of 155CA2, and alleles 1 and 11 of A55CA1 were significantly higher in CAE patients than in normal controls. To prevent spurious associations arising from population admixture, we further conducted TDT tests in the 90 CAE trios. The results of TDT analysis further suggested that microsatellite DNA repeats 85CA, 155CA1, and 155CA2 were associated with CAE. CONCLUSIONS: GABA type-A receptor subunit genes GABRA5 and GABRB3 may be either directly involved in the etiology of CAE in the Chinese population or in linkage disequilibrium with disease-predisposing sites.
BACKGROUND: The cytogenetic analysis of the fragile X affected shows a break point in the q27.3 region of chromosome X. However many carrier females and normal carrier males remain refractory to cytogenetic diagnosis. New DNA probes tightly linked to the fragile X point are now available allowing by the familiar RFLP analysis to detect the carrier members. METHODS: Fragile X syndrome affected families were studied cytogenetically and by the use of DNA probes flanking the fragile X region: 1A1, U6.2, VK21 in the distal region and RN1, 4D-8, cX55.7 in the proximal. RESULTS: The haplotypes from two X fragile syndrome affected families were obtained. These families were informatives for all the DNA probes used. The cytogenetic results obtained agree with the previously inheritance pattern reported. CONCLUSIONS: It is very important to detect the normal male carriers. The determination in one family of the origin of the fragile X mutation is possible by the use of DNA probes.
We performed a nationwide, multicenter study of typical retinitis pigmentosa with reference to the inheritance patterns of the disease. A total of 253 probands were registered during two months of 1989, and an analysis of the parental consanguinity of 182 probands with the method of inbreeding coefficient enabled us to estimate the relative prevalence of genetic types; autosomal recessive trait: 47.6%; autosomal dominant trait: 17.3%; sporadic cases: 34.6%. A comparison of the results with previous studies has indicated a decrease in the prevalence of the autosomal recessive trait and an increase in the sporadic cases, as would be expected from the decrease in consanguineous marriages and offsprings in the past few decades in Japan. X-linked retinitis pigmentosa was rarely identified, but precise evaluation of its frequency needs further investigation.
In studying genetic factors in hearing loss among Chinese hearing-impaired population, a Chinese family with deaf-mute that had been reversion inherited through five generations was found (named pedigree L021). X linked recessive inheritance was hypothesized to be the transmission in this family. A total of 64 members in this family were investigated. Of these, audiometric evaluation was performed on 31 members, including 8 males with deaf-mute. Most affected individuals showed deafness or profound sensorineural hearing loss. Blood samples were obtained from 31 consented individuals in this family. Pedigree analysis indicates a X-linked recessive inheritance pattern in pedigree L021. The pedigree described herein provides an excellent model for further study on the molecular mechanism of congenital deaf-mute.
Atopic disorders (asthma, hay fever, atopic dermatitis) may develop on the basis of a genetic predisposition towards environmental factors. These complex genetic conditions do not follow Mendelian inheritance patterns. Rather, the genetic predisposition for atopic diseases is based on a combination of changes affecting several genes which are involved in a variety of pathophysiological mechanisms. A number of candidate genes for asthma and allergies have already been identified. Today, it seems possible to identify genetic risk profiles related to specific environmental conditions which should lead to an improvement in diagnostic, preventive and therapeutic measures. However, before genetic diagnostic can be implemented in clinical practice, further studies are needed.
BACKGROUND: Federal legislation was passed in 1972 initiating genetic screening and community education about sickle cell disease (SCD). Few assessments have examined the impact of these programs. The aim of this study is to assess existing knowledge about SCD among African-American women in St. Louis, MO. METHODS: We conducted a cross-sectional telephone survey of African-American women, 18-30 years of age. Participants were recruited through random-digit dialing in six ZIP codes with greater than 75% African-American residents. The survey contained questions exploring four content domains about SCD: general knowledge, genetics, management and educational resources. RESULTS: A total of 264 women were contacted; 30% were unable to complete the survey and participate further because they were unaware of SCD. One-hundred-sixty-two women met eligibility criteria, agreed to be surveyed and were included in the study. Ninety-one percent of the participants believed that SCD was a hereditary blood disorder, but only 9.3% understood the inheritance pattern. Eleven percent of the women were unaware of their sickle cell trait status. Most women recognized pain (94%), infections (80%) and strokes (40%) as complications of SCD. CONCLUSION: New strategies are needed to enhance awareness of SCD among African-American women of childbearing age.
Primary cutaneous mucinosis encompasses a wide range of different skin conditions with circumscribed, follicular or diffuse manifestation. For the first time, to our knowledge, we report on the occurrence of so-called "atypical" localized papular mucinosis in the axillary pits of a mother and her (identical) twin daughters presenting as asymptomatic soft minuscule papules. This unique observation allows us to define an autosomal dominant inheritance pattern with a high level of penetrance for this rare skin disease.
The rationale for use of inbred strains of mice in bone research is well recognized and includes: a) practical factors (economics of scale, rapid development of adult status, pre-existing knowledge, down-sized technologies) and b) proven methodologies for genetic studies (polygenic trait analyses, mapping tools, genomic sequencing, methods for gene manipulation). Initial investigations of inbred strains of mice showed that femoral and lumbar vertebral volumetric bone mineral density (BMD, mg/mm(3)) by pQCT varied in excess of 50% for femurs and 9% in vertebral BMD. Two strains - low BMD C57BL/6J (B6) mice and high BMD C3H/HeJ (C3H) - were investigated for insights to their BMD diversity. B6C3F2 females derived from intercrossing B6C3F1s were raised to adult skeletal status at 4 months, then necropsied for phenotyping of bone and genotyping of genomic DNA. 1000 F2 females were genotyped for PCR product polymorphisms on all 19 autosomes at approximately 15 cM. Genome wide analyses for genotype-phenotype correlations showed 10 chromosomes (Chrs) carried genes for femoral and 7 Chrs for vertebral BMD. LOD scores ranged from 2.90 to 24.4, and percent of F2 variance accounted for ranged from 1 to 10%. Analyses of main effects revealed both dominant-recessive and additive inheritance patterns. Both progenitor strains carried alleles with positive and negative effects on BMD of each bone sites. A remarkable array of additonal skeletal phenotypes (femur and vertebral geometry, strength measures, serum markers) also proved polygenic in nature, with complex segregation patterns. Verification of BMD quantitative trait loci (QTLs) was undertaken by creating congenic B6 strains carrying individual QTL regions from C3H. Following 6 cycles of backcrossing a QTL-containing region from C3H to the B6 strain, N6F2 congenic strain mice were aged to 4 months, then genotyped for the QTL region and phenotyped for skeletal traits. Comparison of mice homozygous for C3H alleles versus homozygous for B6 alleles in the QTL regions showed that femoral BMD increased or decreased significantly in congenic strains, as was predicted from F2 data. Gender differences specific to BMD QTLs have been revealed, as have more than 30 additional phenotypes associated with cortical and trabecular structural parameters and biomechanical properties.
Organisms and the symbionts they harbor may experience opposing forces of selection. In particular, the contrasting inheritance patterns of maternally transmitted symbionts and their host's nuclear genes can engender conflict among organizational levels over the optimal host offspring sex ratio. This study uses a male-killing Wolbachia endosymbiont and its host Drosophila innubila to experimentally address the potential for multilevel selection in a host-symbiont system. We show that bacterial density can vary among infected females, and that females with a higher density have a more female-biased offspring sex ratio. Furthermore, bacterial density is an epigenetic and heritable trait: females with a low bacterial load have daughters with a lower-than-average bacterial density, whose offspring then experience less severe male-killing. For infected sons, the probability of embryonic mortality increases with the bacterial density in their mothers. The frequency distribution of Wolbachia density among individual D. innubila females, and therefore the dynamics of infection within populations of these flies, results both from processes affecting the growth and regulation of bacterial populations within cytoplasmic lineages and from selection among cytoplasmic lineages that vary in bacterial density. Estimates of effective population size of Wolbachia within cytoplasmic lineages and of D. innubila at the host population level suggest that selection among cytoplasmic lineages is likely to overwhelm the results of selection within lineages.