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PubMed2003

The effects of hydrogen peroxide promoted by homocysteine and inherited catalase deficiency on human hypocatalasemic patients.

Elevated plasma homocysteine can generate oxygen free radicals and hydrogen peroxide. The enzyme catalase is involved in the protection against hydrogen peroxide. We examined the effect of oxidative stress promoted by homocysteine on erythrocyte metabolism (blood hemoglobin, MCV, folate, B12, serum LDH, LDH isoenzymes, haptoglobin) in the oxidative stress sensitive Hungarian patients with inherited catalase deficiency. The plasma homocysteine (HPLC method, Bio-Rad), folate, B12 (capture binding assay, Abbott), blood hemoglobin concentrations, blood catalase activity (spectrophotometric assay of hydrogen peroxide), and MCV values were determined in 7 hypocatalasemic families including hypocatalasemic (male:12, female:18) patients and their results were compared to those of the normocatalasemic (male:17 female: 12) family members. We found decreased (p <.036) folate (ng/ml) concentrations (male hypocatalasemic 5.44 +/- 2.81 vs. normocatalasemic 7.56 +/- 1.97, female 5.01 +/- 1.93 vs. 6.61 +/- 1.91), blood hemoglobin (p <.010, male:140.2 +/- 11.0 vs. 153.6 +/- 11.6 g/l, female: 128.4 +/- 10.9 vs. 139.6 +/- 9.2 g/l). Increased levels of MCV (p <.001) were detected in hypocatalasemic patients (male: 98.6 +/- 3.4 vs. 90.1 +/- 7.5 fl, female: 95.9 +/- 3.9 vs. 90.1 +/- 2.5 fl), plasma homocysteine (p <.049, male: 9.72 +/- 3.61 vs. 7.36 +/- 2.10 umol/l, female: 9.06 +/- 3.10 vs. 6.84 +/- 2.50 umol/l) and not significant (p >.401) plasma B12 (male: 336 +/- 108 vs. 307 +/- 76 pg/ml, female: 373 +/- 180 vs. 342 +/- 75 pg/ml). The serum markers of hemolysis (LDH, LDH isoenzymes, haptoglobin) did not show significant (p >.228) signs of oxidative erythrocyte damage. We report firstly on increased plasma homocysteine concentrations in inherited catalase deficiency. The increased plasma homocysteine and inherited catalase deficiency together could promote oxidative stress via hydrogen peroxide. The patients with inherited catalase deficiency are more sensitive to oxidative stress of hydrogen peroxide than the normocatalasemic family members. This oxidative stress might be responsible for the decreased concentration of the blood hemoglobin via the oxidation sensitive folate and may contribute to the early development of arteriosclerosis and diabetes in these patients.

Acatalasia↗
PubMed2000

Reciprocal inheritance of centrosomes in the parthenogenetic hymenopteran Nasonia vitripennis.

BACKGROUND: In the majority of animals, the centrosome-the microtubule-organizing center of the cell-is assembled from components of both the sperm and the egg. How the males of the insect order Hymenoptera acquire centrosomes is a mystery, as they originate from virgin birth. RESULTS: To address this issue, we observed centrosome, spindle and nuclear behavior in real time during early development in the parthenogenetic hymenopteran Nasonia vitripennis. Female meiosis was identical in unfertilized eggs. Centrosomes were assembled before the first mitotic division but were inherited differently in unfertilized and fertilized eggs. In both, large numbers of asters appeared at the cortex of the egg after completion of meiosis. In unfertilized eggs, the asters migrated inwards and two of them became stably associated with the female pronucleus and the remaining cytoplasmic asters rapidly disappeared. In fertilized eggs, the Nasonia sperm brought in paternally derived centrosomes, similar to Drosophila melanogaster. At pronuclear fusion, the diploid zygotic nucleus was associated only with paternally derived centrosomes. None of the cytoplasmic asters associated with the zygotic nucleus and, as in unfertilized eggs, they rapidly degenerated. CONCLUSIONS: Selection and migration of the female pronucleus is independent of the sperm and its aster. Unfertilized male eggs inherit maternal centrosomes whereas fertilized female eggs inherit paternal centrosomes. This is the first system described in which centrosomes are reciprocally inherited. The results suggest the existence of a previously undescribed mechanism for regulating centrosome number in the early embryo.

Animals↗
PubMed2003

Overview of inherited metabolic disorders causing cardiovascular disease.

Inherited metabolic disorders contribute importantly to adverse cardiovascular outcomes and affect all tissue types. This review summarizes some of the more important aspects. In the venous system, heterozygosities for the factor V Leiden and prothrombin 20210G > A mutations are common and occur in 4% and 1%, respectively, of caucasians. They confer a 2- to 3- fold increase in risk of venous, but not arterial, thrombosis. Marfan syndrome affects the systemic circulation and has a population prevalence of about 1 in 4000. The more than 200 mutations responsible are in the fibrillin-1 gene (15q21.1) and mediate the characteristic skeletal, lens and aortic changes. There are two potentially lethal inherited disorders of cardiac conduction, the long QT and Brugada syndromes. The prevalence for each is about 1 in 10,000. On the other hand, autosomal dominant hypertrophic cardiomyopathies are relatively common, at 1 in 500, but with variable penetrance. Mutations are in the sarcomere proteins and more than 140 are known. Hypertrophic cardiomyopathy may be confused with Fabry disease, for which effective treatment is now available. Mutations in several genes have been shown to produce dilated cardiomyopathy in the young, but there is as yet no specific treatment. In fatty acid oxidation disorders, arrhythmias and cardiomyopathy occur during acute decompensation. An important recently established cause of cardiomyopathy is carnitine transporter defect; it is treated effectively with oral carnitine. The autosomal dominant arrhythmogenic right ventricular dysplasia occurs with a prevalence of about 1 in 15,000 and presents with arrythmias and a dilated right ventricle. The mutations responsible have been mapped to chromosomes 1, 2, 10 and 14. Lysosomal storage disorders, the Ehlers-Danlos syndrome and other connective-tissue disorders affect cardiac valves and vessels. In addition to the relatively common inherited lipoprotein disorders familial hypercholesterolaemia and familial combined hyperlipidaemia, an important dominantly inherited lipid variable contributing to coronary risk is lipoprotein(a). The gene is localized to chromosome 6 and there is full expression in childhood. Elevated lipoprotein(a) levels contribute to the occurrence and severity of early-onset coronary disease and add to the already enhanced risk in patients with familial hypercholesterolaemia.

Arrhythmias, Cardiac↗
PubMed2001

Deconstructing Golgi inheritance.

Eukaryotic cells use a variety of strategies to inherit the Golgi apparatus. During vertebrate mitosis, the Golgi reorganizes dramatically in a process that seems to be driven by the reversible fragmentation of existing Golgi structures and the temporary redistribution of Golgi components to the endoplasmic reticulum. Several proteins that participate in vertebrate Golgi inheritance have been identified, but their detailed functions remain unknown. A comparison between vertebrates and other eukaryotes reveals common mechanisms of Golgi inheritance. In many cell types, Golgi stacks undergo fission early in mitosis. Some cells exhibit a further Golgi breakdown that is probably due to a mitotic inhibition of membrane traffic. In all eukaryotes examined, Golgi inheritance involves either the partitioning of pre-existing Golgi elements between the daughter cells or the emergence of new Golgi structures from the endoplasmic reticulum, or some combination of these two pathways.

Animals↗
PubMed1999

Epigenetic inheritance at the agouti locus in the mouse.

Epigenetic modifications have effects on phenotype, but they are generally considered to be cleared on passage through the germ line in mammals, so that only genetic traits are inherited. Here we describe the inheritance of an epigenetic modification at the agouti locus in mice. In viable yellow ( A(vy)/a) mice, transcription originating in an intra-cisternal A particle (IAP) retrotransposon inserted upstream of the agouti gene (A) causes ectopic expression of agouti protein, resulting in yellow fur, obesity, diabetes and increased susceptibility to tumours. The pleiotropic effects of ectopic agouti expression are presumably due to effects of the paracrine signal on other tissues. Avy mice display variable expressivity because they are epigenetic mosaics for activity of the retrotransposon: isogenic Avy mice have coats that vary in a continuous spectrum from full yellow, through variegated yellow/agouti, to full agouti (pseudoagouti). The distribution of phenotypes among offspring is related to the phenotype of the dam; when an A(vy) dam has the agouti phenotype, her offspring are more likely to be agouti. We demonstrate here that this maternal epigenetic effect is not the result of a maternally contributed environment. Rather, our data show that it results from incomplete erasure of an epigenetic modification when a silenced Avy allele is passed through the female germ line, with consequent inheritance of the epigenetic modification. Because retrotransposons are abundant in mammalian genomes, this type of inheritance may be common.

Agouti Signaling Protein↗
PubMed2005

Prevalence of inherited prothrombotic abnormalities and central venous catheter-related thrombosis in haematopoietic stem cell transplants recipients.

In this prospective study, we assessed the incidence of central venous catheter (CVC)-related thrombosis in haematopoietic stem cell transplant (HSCT) recipients. We determined the contribution of inherited prothrombotic abnormalities in blood coagulation to CVC-related thrombosis in these patients. The study was conducted between May 2002 and September 2004. CVCs were externalized, nontunneled, polyurethane double lumen catheters. Before catheter insertion, laboratory prothrombotic markers included factor V Leiden, the prothrombin gene Gly20210A mutation, plasma antithrombin levels, and protein C and S activity. All patients were systematically examined by ultrasonography just before, or <24 h after, catheter removal, and in case of clinical signs of thrombosis. A total of 171 patients were included during the 28-month study period. Five (2.9%) and three (1.7%) patients had evidence of protein C and protein S deficiency, respectively. Only one patient had an antithrombin deficiency (0.6%). In total, 10 patients (5.8%) were heterozygous for the factor V Leiden mutation, and one patient had heterozygous prothrombin G20210A mutation (0.6%). We observed a CVC-related thrombosis in 13 patients (7.6%). Thrombosis was diagnosed in four out of 20 patients (20%) with a inherited prothrombotic abnormality compared to nine of 151 patients (6%) who did not have a thrombophilic marker (relative risk 3.3 CI 95% 1.1-9.9). Our results suggest that inherited prothrombotic abnormalities contribute substantially to CVC-related thrombosis in HSCT recipients. In view of physicians' reluctance to prescribe prophylactic anticoagulant treatment in these patients, a priori determination of inherited prothrombotic abnormalities may form a basis to guide these treatment decisions.

Blood Coagulation Factors↗
PubMed2006

Ptc1p regulates cortical ER inheritance via Slt2p.

Studies in the yeast Saccharomyces cerevisiae have shown that the inheritance of endoplasmic reticulum (ER), mitochondria, and vacuoles involves the capture of a tubular structure at the bud tip. Ptc1p, a serine/threonine phosphatase, has previously been shown to regulate mitochondrial inheritance by an unknown mechanism. Ptc1p regulates the high osmolarity glycerol mitogen-activated protein kinase (MAPK) pathway and has also been implicated in the cell wall integrity (CWI) MAPK pathway. Here we show that the loss of Ptc1p or the Ptc1p binding protein, Nbp2p, causes a prominent delay in the delivery of ER tubules to the periphery of daughter cells and results in a dramatic increase in the level of phosphorylated Slt2p, the MAPK in the CWI pathway. Either loss of Slt2p or inhibition of the CWI pathway by addition of sorbitol, suppresses the ER inheritance defect in the ptc1Delta and nbp2Delta mutants. Our findings indicate that Ptc1p and Nbp2p regulate ER inheritance through the CWI MAPK pathway by modulating the MAPK, Slt2p.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Disruption of doubly uniparental inheritance of mitochondrial DNA in hybrid mussels (Mytilus edulis x M. galloprovincialis).

Blue mussels of the genus Mytilus have an unusual mode of mitochondrial DNA inheritance termed doubly uniparental inheritance (DUI). Females are homoplasmic for the F mitotype which is inherited maternally, whereas males are heteroplasmic for this and the paternally inherited M mitotype. In areas where species distributions overlap a varying degree of hybridization occurs; yet genetic differences between allopatric populations are maintained. Observations from natural populations and previous laboratory experiments suggest that DUI may be disrupted by hybridization, giving rise to heteroplasmic females and homoplasmic males. We carried out controlled laboratory crosses between Mytilus edulis and M. galloprovincialis to produce pure species and hybrid larvae of known parentage. DNA markers were used to follow the fate of the F and M mitotypes through larval development. Disruption of the mechanism which determines whether the M mitotype is retained or eliminated occurred in an estimated 38% of M. edulis x M. galloprovincialis hybrid larvae, a level double that previously observed in adult mussels from a natural M. edulis x M. galloprovincialis hybrid population. Furthermore, reciprocal hybrid crosses exhibited contrasting types of DUI disruption. The results indicate that disruption of DUI in hybrid mussels may be associated with increased mortality and hence could be a factor in the maintenance of genetic integrity for each species.

Animals↗
PubMed1998

Polygenic inheritance and micro/minisatellites.

While it has often been stated that the identification of the genes involved in complex polygenic traits may be extremely difficult, the principles learned in the past century about single gene-single disease inheritance may not be relevant to polygenic inheritance. A new paradigm specific to complex disorders may be needed. It is proposed that micro- and minisatellite polymorphisms play a role in the expression of many genes. As a result, these genes exist in the population with many functional alleleomorphic variants. While each variant has only a modest effect on a given phenotype, because the variants are common, and most quantitative traits are controlled by a number of genes, there is a reasonable probability that an individual will inherit a threshold number of functional variants beyond which there is an appreciable effect on the phenotype. Twelve different aspects of such a new model for complex inheritance, some corollary implications, and three examples of its immediate application, are presented with the hope that the model may allow an acceleration of the identification of the genes involved in complex polygenic disorders.

DNA↗
PubMed1998

Quality of life during menstruation in patients with inherited bleeding disorders.

Menorrhagia is a common and major problem for patients with inherited bleeding disorders, especially vWD. Quality of life during menstruation was assessed in 99 patients with inherited bleeding disorders including vWD (n = 57), carriers of haemophilia A (n = 17), carriers of haemophilia B (n = 7) and FXI deficiency (n = 18), and comparison was performed with an age-matched control group (n = 69). A questionnaire was used that included four main sections: (i) general health, (ii) health and daily activities, (iii) dysmenorrhea and (iv) quality of life during the menstrual period. Although patients with inherited bleeding disorders felt that their health (in general) was very good, they had significantly poorer quality of life on all the scales used than controls. Thirty-nine per cent reported having cut down on the amount of time spent on work and other activities as a result of their menstruation; 47% felt that they accomplished less than they would like during this period, 38% felt that they were limited in the kind of work and other activities that they could do, and 40% found that it took extra effort to perform their work. Fifty-one per cent experienced moderate, severe or very severe dysmenorrhoea. Quality of life was statistically poorer in patients with vWD, menstrual scores > 100 according to the pictorial blood assessment chart (PBAC), those who had periods > or = 8 days and those who experienced flooding or passage of clots. In conclusion, menstruation has a negative effect on the quality of life in patients with inherited bleeding disorders especially in those with objectively confirmed menorrhagia.

Adolescent↗
PubMed1999

Assessment of menstrual blood loss and gynaecological problems in patients with inherited bleeding disorders.

Menstrual blood loss and gynaecological problems in patients with inherited bleeding disorders were assessed in this study. One hundred and sixteen women, including 66 with von Willebrand's disease (vWD), 30 carriers of haemophilia and 20 with factor XI (FXI) deficiency were interviewed and their gynaecological history obtained. Their case records were also reviewed and menstrual loss was objectively assessed using a pictorial blood assessment chart (PBAC). Comparison with an age-matched control group (69 women) was performed. Menorrhagia (PBAC score> 100) was confirmed in 74%, 57% and 59% of women with vWD, carriers of haemophilia and FXI deficiency, respectively, in comparison with 29% in the control group (P = 0.001). PBAC scores were higher in vWD patients with a von Willebrand factor activity (vWF:Ac) of </= 30 IU dL-1 compared to those with higher levels, but the difference was not statistically significant. However, there was no relation between PBAC score and the severity of the disease in FXI deficient patients and carriers of haemophilia. Duration of menstruation was significantly longer (P = 0.001) and episodes of flooding was significantly more common (P = 0.001) in patients with inherited bleeding disorders compared to the control group. However, there was no difference in the passage of clots during menstruation. Forty-seven per cent of patients with inherited bleeding disorders had consultations with their family practitioner or gynaecologist for menorrhagia, 36% had medical treatment and 27% had surgical procedures, including 10 hysterectomies. Post-operative bleeding followed in four out of 28 cases of hysteroscopy and/or dilatation and curettage. Bleeding complications following hysterectomy were reported in five out of 10 patients. In conclusion, menorrhagia is a common and major problem in patients with inherited bleeding disorders, especially vWD. Increased awareness among gynaecologists and haematologists of the high prevalence of menorrhagia and the treatment options available is necessary for optimal management of these patients. Appropriate preoperative assessment and haemostatic control during any gynaecological procedure, however minor, and in collaboration with the local haemophilia centre is essential to minimize risks of haemorrhagic complications.

Adolescent↗
PubMed2001

Inherited thrombophilia: a possible cause of in utero vascular thrombosis in children with intestinal atresia.

BACKGROUND: Congenital atresia of the small and large intestine is thought to evolve from in utero mesenteric vascular occlusion of the corresponding intestinal segment. Because spontaneous thrombosis recently has been described in association with inherited thrombophilia, the authors wondered if inherited thrombophilia also might be found in babies with intestinal atresia. METHODS: Genetic analysis was done on 28 children treated for congenital intestinal atresia. DNA was analyzed for point mutations to detect the 2 most common types of inherited thrombophilia, the G1691A mutation in the factor V gene (factor V Leiden) and the G20210A mutation in the prothrombin gene. In addition, other genetic risk factors for thrombosis were analyzed including the C677T mutation in the methylenetetrahydrofolate reductase gene (MTHFR) and 2 polymorphisms of the factor VII gene (the R353Q and the hypervariable region 4 polymorphisms). RESULTS: The factor V Leiden mutation was present in 5 of 28 (18%) children treated for congenital intestinal atresia. This is increased significantly when compared with the reported carrier frequency of 3% to 7% in the general population and a reported carrier rate of 4.2% in the local population (P <.005). The R353Q polymorphism of the factor VII gene, specifically the RR genotype, was noted in 85% of patients with atresia with an expected frequency of 64% (P <.008). There were no significant associations noted between mutations in the prothrombin gene, the MTHFR gene, or the hypervariable region of the factor VII gene. CONCLUSIONS: The factor V Leiden mutation and the RR subtype of the R353Q polymorphism of the factor VII gene are seen at an increased frequency in children with congenital intestinal atresia. This suggests that inherited thrombophilia may play a role in the etiology of these in utero mesenteric thrombotic events.

Cohort Studies↗
PubMed2001

Inherited epilepsies.

Epilepsy may be acquired or inherited. At least one half of epilepsy is genetic in origin; this figure is likely higher in children regardless of whether seizures are generalized or partial. Inherited epilepsies are classified as benign, cryptogenic, or symptomatic depending on associated clinical, electrographic, and neuroimaging features. To date, genetic mutations in the idiopathic inherited epilepsies affect channel function within the central nervous system; genes underlying symptomatic epilepsies are more heterogeneous. Accurate diagnosis of an inherited epilepsy syndrome provides useful prognostic information; it also may help guide diagnostic evaluation, including request for specific gene testing. In the near future, the relationship between genetic defect and response to specific anticonvulsants may also be better defined.

Adolescent↗
PubMed2001

The importance of cultural inheritance.

Cultural inheritance refers to the storage and transmission of information by communication, imitation, teaching and learning. It is transmitted by the brain rather than by genes. However, it does have a genetic basis, the genes involved determining the structure of the brain. Cultural inheritance is considered to be the latest stage in the evolution of heredity. It is thought to have evolved by epigenetic mechanisms from genetic inheritance. This article proposes that cultural inheritance underlies normal behaviour and mental disorders.

Animals↗
PubMed2000

Autosomal dominantly inherited generalized basaloid follicular hamartoma syndrome: report of a new disease in a North Carolina family.

BACKGROUND: An 8-year-old girl presented with hundreds of milia, measuring 1 to 2 mm; comedone-like lesions; skin-colored and hyperpigmented papules on the face, scalp, ears, neck, upper trunk, and lower arms along with diffuse scalp hypotrichosis; and pinpoint palm/sole pits. Onset was in early childhood and the disease was historically present in 6 generations. OBJECTIVE: Our objectives were to delineate the clinical and histopathologic features and mode of inheritance as a base for gene studies. METHODS: Eighteen family subjects were studied. Twenty-six skin biopsy specimens were examined. A detailed pedigree was constructed. A complete literature search was done concerning diseases with generalized basaloid follicular hamartomas. RESULTS: The lesions were basaloid follicular hamartomas and other folliculocentric abnormalities. Inheritance was autosomal dominant. Extensive literature search confirmed the finding of a unique genodermatosis. CONCLUSION: A new genodermatosis termed dominantly inherited generalized basaloid follicular hamartoma syndrome was defined by delineating its clinical and histopathologic features and mode of inheritance and by extensive literature review.

Adolescent↗
PubMed2005

Age-specific incidence of inherited versus sporadic cancers: a test of the multistage theory of carcinogenesis.

Knudson [Knudson, A. G. (1971) Proc. Natl. Acad. Sci. USA 68, 820-823] suggested that progression of retinoblastoma follows from two mutational events. Individuals who inherit one mutated gene copy should follow an age-onset pattern set by only a single rate-limiting step for transformation, whereas normal individuals should follow an age-onset pattern set by two rate-limiting events. Knudson's analysis of inherited and sporadic cases of retinoblastoma supported this prediction. However, retinoblastoma has a peculiar age-onset pattern concentrated in early life, because the retinal tissue completes most of its cell division by 5 years of age. Here, I compare age-specific incidences of inherited and sporadic forms of colon cancer, a much more typical form of human cancer. My simple mathematical analysis based on multistage theory explains the observed differences in age-onset patterns between inherited and sporadic cases. I also analyze recent retinoblastoma data and provide a mathematical analysis and interpretation. My analysis supports Knudson's two-hit theory but is much simpler and easier to understand than the original mathematical theory, which was based on a complicated model of cell division in the retina. My simpler theory for retinoblastoma makes clear the common basis for understanding multistage progression in tissues as different as the retina and colon.

Adult↗
PubMed1991

Maternal inheritance of centrosomes in mammals? Studies on parthenogenesis and polyspermy in mice.

The centrosome, the microtubule-organizing center of the cell, is introduced typically by the sperm at fertilization. In some mammals, however, this paternal pattern of inheritance appears to be violated. The hypothesis that the centrosome is maternally inherited was tested during parthenogenesis, polyspermy, and polygyny as well as after recovery from microtubule inhibition at first mitosis. During parthenogenesis the paternal contribution was absent, and in polyspermy the paternal contribution was multiplied. Haploid and diploid parthenogenotes as well as polyspermic and digynic fertilized eggs each segregated their centrosomes to organize a bipolar mitotic apparatus. Oocytes recovering from a nocodazole block formed two normal bipolar mitotic apparatus; the paternal chromosomes aligned at one spindle equator, while the maternal chromosomes were found at the other. These results show that the centrosome is maternally inherited from cytoplasmic sites in the mouse. The evolutionary switch from paternal to maternal inheritance in mammals might be related to the additional dangers that parthenogenesis represents: a threat to the life of the mother as well as to the life of the fetus.

Animals↗
PubMed2002

Inheritance pattern and elemental composition of enamel affected by hypomaturation amelogenesis imperfecta.

Hypomaturation amelogenesis imperfecta (AI) is characterized clinically by enamel of normal thickness that is hypomineralized, mottled, and detaches easily from the underlying dentin. Autosomal dominant, autosomal recessive, X-linked, and sporadic modes of inheritance have been documented. The present study investigated the elemental composition of the enamel of teeth from individuals demonstrating clinical hypomaturation AI from families representing three of these patterns of inheritance. The aim of the study was to determine if there was any commonality in microscopic phenotype of this defect between families demonstrating the various inheritance patterns. One section from each tooth was microradiographed and then viewed in a scanning electron microscope (SEM) equipped with an ultrathin window energy-dispersive x-ray spectroscopy (EDX) detector. In the SEM, prisms and constituent crystals in discrete areas appeared to be largely obscured by an amorphous material. EDX analysis showed enamel outside these areas to have a composition indistinguishable from control teeth. However, within these affected areas there was a large increase in carbon content (up to a fivefold increase). In some teeth there was also a detectable but smaller increase in the relative amounts of nitrogen or oxygen. The results suggest the defect in these teeth with a common clinical phenotype, irrespective of the pattern of inheritance, demonstrates a commonality in microscopic phenotype. The large increase in carbon content, not matched by an equivalent increase in nitrogen or oxygen, suggests a possible increased lipid content. In those teeth with elevated nitrogen levels there may also be retained protein.

Amelogenesis Imperfecta↗