Elevated conversion of alpha-2-macroglobulin to the complexed form in gingival crevicular fluid from adult periodontitis patients

The broad spectrum protease inhibitor, alpha 2-macgrolobulin (alpha 2M), is one of the host's principal regulators of both endogenous and exogenous proteases and is likely to have an important role in the regulation of proteolytic activity at inflammatory sites. We have determined the amount of complexed (com alpha 2M) and total alpha 2M (tot alpha 2M) in gingival crevicular fluid (GCF) harvested from shallow and deep sites in adult periodontitis (AP) patients (n = 21). An ELISA technique was developed to measure both forms of alpha 2M in the same sample utilizing a monoclonal antibody (MAb) specific for the complexed form. In addition, protease activity towards human serum albumin (Prot1), transferrin (Prot2) and N alpha-benzoyl-L-arginine 7-amido-4-methylcoumarin-hydrochloride (BAAMc; Prot3) were determined in a second GCF sample from the same site. Plasma alpha 2M concentrations were only positively correlated (p = 0.0163) with GCF tot alpha 2M from highly inflamed sites. We observed a significant positive correlation between tot alpha 2M and proteolytic activity in GCF from deep sites but not from shallow sites (Prot1: p = 0.002; Prot2: p = 0.005). A similar correlation between tot alpha 2M and proteolytic activity was found at highly inflamed sites (Prot1: p = 0.014; Prot2: p = 0.002). A very high proportion of the tot alpha 2M in GCF was in the complexed form at both shallow (71.14% +/- 29.13) and deep sites (68.17% +/- 28.5) Com alpha 2M was positively correlated with proteolytic activity only in deep sites (Prot1: p = 0.015; Prot2: p = 0.031). Our results suggest that the concentration of tot alpha 2M in the gingival crevice is positively associated with the amount of proteolytic activity at the site and that protease activities in GCF may only partly explain the high percentage conversion alpha 2M to the complexed form. The high level of alpha 2M inactivation in GCF from AP patients reported here may have significance not only in view of its role as a broad spectrum protease inhibitor but also through the differential effects of native vs complexed alpha 2M on the regulation of immune responses.

Production of intracellular amyloid-containing fragments in hippocampal neurons expressing human amyloid precursor protein and protection against amyloidogenesis by subtle amino acid substitutions in the rodent sequence

A distinguishing feature of Alzheimer's disease (AD) is the deposition of amyloid plaques in brain parenchyma. These plaques arise by the abnormal accumulation of beta A4, a proteolytic fragment of amyloid precursor protein (APP). Despite the fact that neurons are dramatically affected in the course of the disease, little is known about the neuronal processing of APP. To address this question we have expressed in fully mature, synaptically active rat hippocampal neurons, the neuronal form of human APP (APP695), two mutant forms of human APP associated with AD, and the mouse form of APP (a species known not to develop amyloid plaques). Protein expression was achieved via the Semliki Forest Virus system. Expression of wild type human APP695 resulted in the secretion of beta A4-amyloid peptide and the intracellular accumulation of potential amyloidogenic and non-amyloidogenic fragments. The relative amount of amyloid-containing fragments increased dramatically during expression of the clinical mutants, while it decreased strongly when the mouse form of APP was expressed. 'Humanizing' the rodent APP sequence by introducing three mutations in the beta A4-region also led to increased production of amyloid peptide to levels similar to those obtained with human APP. The single Gly601 to Arg substitution alone was sufficient to triple the ratio of beta A4-peptide to non-amyloidogenic p3-peptide. Due to the capacity of these cells to secrete and accumulate intracellular amyloid fragments, we hypothesize that in the pathogenesis of AD there is a positive feed-back loop where neurons are both producers and victims of amyloid, leading to neuronal degeneration and dementia.(ABSTRACT TRUNCATED AT 250 WORDS)

Cloning, sequencing, and phenotypic analysis of laf1, encoding the flagellin of the lateral flagella of Azospirillum brasilense Sp7

Azospirillum brasilense can display a single polar flagellum and several lateral flagella. The A. brasilense Sp7 gene laf1, encoding the flagellin of the lateral flagella, was isolated and sequenced. The derived protein sequence is extensively similar to those of the flagellins of Rhizobium meliloti, Agrobacterium tumefaciens, Bartonella bacilliformis, and Caulobacter crescentus. An amino acid alignment shows that the flagellins of these bacteria are clustered and are clearly different from other known flagellins. A laf1 mutant, FAJ0201, was constructed by replacing an internal part of the laf1 gene by a kanamycin resistance-encoding gene cassette. The mutant is devoid of lateral flagella but still forms the polar flagellum. This phenotype is further characterized by the abolishment of the capacities to swarm on a semisolid surface and to spread from a stab inoculation in a semisolid medium. FAJ0201 shows a normal wheat root colonization pattern in the initial stage of plant root interaction.

Targeted inactivation of the mouse alpha 2-macroglobulin gene

The mouse alpha 2-macroglobulin gene was inactivated in embryonic stem cells by homologous recombination. Liver alpha 2-macroglobulin mRNA and plasma protein was absent in homozygotes and reduced to 50% in heterozygotes. alpha 2-Macroglobulin-deficient mice were viable and produced normally sized litters with normal sex ratio over 3 generations. Characterization of adult homozygotes included diets with different fat content, treatments with endotoxin, bleomycin, carbon tetrachloride, and ethionine to test for immune system, lung, liver, and pancreas toxicity, respectively. Knock-out mice were more resistant to endotoxin but more sensitive to a choline-free diet supplemented with ethionine. Regulation of murinoglobulin mRNA expression during pregnancy was analyzed as a possible back-up mechanism for the deficiency in alpha 2-macroglobulin. In addition, expression of mRNA was studied, coding for alpha 2-macroglobulin receptor/lipoprotein receptor-related protein, low density lipoprotein receptor, and very low density lipoprotein receptor and for some common ligands, i.e. apolipoprotein E, lipoprotein lipase, and the 44-kDa heparin binding protein. Their differential regulation in the knock-out mice relative to C57B1 mice was evident and is discussed. The impressive 15-fold increase in maternal liver murinoglobulin mRNA at partum in the knock-out mice indicated increased consumption, compared to only 4-fold in normal mice. Thus, murinoglobulin appears as the major proteinase inhibitor around partum, obviously solicited to a much greater extend in alpha 2-macroglobulin-deficient mice.

Expression of mouse alpha-macroglobulins, lipoprotein receptor-related protein, LDL receptor, apolipoprotein E, and lipoprotein lipase in pregnancy

The expression of the proteinase inhibitors of the alpha-macroglobulin family and of their clearance receptor was analyzed in the mouse during pregnancy, embryonal development, and adolescence. In total we studied seven partners of a complicated network of interactions in proteolysis and lipid metabolism:alpha-2-macroglobulin, murinoglobulin, the alpha-2-macroglobulin receptor/lipoprotein receptor related protein, the murine equivalent of the receptor associated protein or the 44 kDa heparin binding protein, the low density lipoprotein receptor, apolipoprotein E, and lipoprotein lipase. The data demonstrate that: i) the regulation of expression of mouse tetrameric alpha-2-macroglobulin results in very constant levels, similar to alpha-2-macroglobulin in humans; ii) single chain murinoglobulin, not alpha-2-macroglobulin, is subject to regulation of expression during pregnancy, around birth, and in adolescence; iii) an important role seems implicated for the alpha-2-macroglobulin receptor in placental lipid metabolism, probably making it the most important lipoprotein receptor to supply the fetus; iv) the massive increase in apolipoprotein E synthesis in uterus and placenta accentuate the changed lipid metabolism during pregnancy to an apolipoprotein E-based uptake by the alpha-2-macroglobulin receptor/lipoprotein receptor related protein; v) the increased expression of lipoprotein lipase underlines its role in the generation of free fatty acids in uterus and placenta as another mechanism of supply, next to receptor mediated endocytosis of lipoproteins.

Isolation and characterisation of plant defensins from seeds of Asteraceae, Fabaceae, Hippocastanaceae and Saxifragaceae

From seeds of Aesculus hippocastanum, Clitoria ternatea, Dahlia merckii and Heuchera sanguinea five antifungal proteins were isolated and shown to be homologous to plant defensins previously characterised from radish seeds and gamma-thionins from Poaceae seeds. Based on the spectrum of their antimicrobial activity and the morphological distortions they induce on fungi the peptides can be divided into two classes. The peptides did not inhibit any of three different alpha-amylases.

Small cysteine-rich antifungal proteins from radish: their role in host defense

Radish seeds have previously been shown to contain two homologous, 5-kD cysteine-rich proteins designated Raphanus sativus-antifungal protein 1 (Rs-AFP1) and Rs-AFP2, both of which exhibit potent antifungal activity in vitro. We now demonstrate that these proteins are located in the cell wall and occur predominantly in the outer cell layers lining different seed organs. Moreover, Rs-AFPs are preferentially released during seed germination after disruption of the seed coat. The amount of released proteins is sufficient to create a microenvironment around the seed in which fungal growth is suppressed. Both the cDNAs and the intron-containing genomic regions encoding the Rs-AFP preproteins were cloned. Transcripts (0.55 kb) hybridizing with an Rs-AFP1 cDNA-derived probe were present in near-mature and mature seeds. Such transcripts as well as the corresponding proteins were barely detectable in healthy uninfected leaves but accumulated systemically at high levels after localized fungal infection. The induced leaf proteins (designated Rs-AFP3 and Rs-AFP4) were purified and shown to be homologous to seed Rs-AFPs and to exert similar antifungal activity in vitro. A chimeric Rs-AFP2 gene under the control of the constitutive cauliflower mosaic virus 35S promoter conferred enhanced resistance to the foliar pathogen Alternaria longipes in transgenic tobacco. The term "plant defensins" is proposed to denote these defense-related proteins.

Small cysteine-rich antifungal proteins from radish: their role in host defense

Radish seeds have previously been shown to contain two homologous, 5-kD cysteine-rich proteins designated Raphanus sativus-antifungal protein 1 (Rs-AFP1) and Rs-AFP2, both of which exhibit potent antifungal activity in vitro. We now demonstrate that these proteins are located in the cell wall and occur predominantly in the outer cell layers lining different seed organs. Moreover, Rs-AFPs are preferentially released during seed germination after disruption of the seed coat. The amount of released proteins is sufficient to create a microenvironment around the seed in which fungal growth is suppressed. Both the cDNAs and the intron-containing genomic regions encoding the Rs-AFP preproteins were cloned. Transcripts (0.55 kb) hybridizing with an Rs-AFP1 cDNA-derived probe were present in near-mature and mature seeds. Such transcripts as well as the corresponding proteins were barely detectable in healthy uninfected leaves but accumulated systemically at high levels after localized fungal infection. The induced leaf proteins (designated Rs-AFP3 and Rs-AFP4) were purified and shown to be homologous to seed Rs-AFPs and to exert similar antifungal activity in vitro. A chimeric Rs-AFP2 gene under the control of the constitutive cauliflower mosaic virus 35S promoter conferred enhanced resistance to the foliar pathogen Alternaria longipes in transgenic tobacco. The term "plant defensins" is proposed to denote these defense-related proteins.

Isolation of Ala1-proctolin, the first natural analogue of proctolin, from the brain of the Colorado potato beetle

Methanolic head and brain extracts of the Colorado potato beetle contain several myotropins, active in the Locusta oviduct motility assay. Reversed phase high performance liquid chromatography (RP HPLC) gave evidence for the presence of three myotropic factors, with retention times close to that of proctolin. Both strongly stimulated the frequency, amplitude and tonus of the myogenic oviduct contractions. Gas phase sequencing and FAB-MS revealed that, besides proctolin (Arg-Tyr-Leu-Pro-Thr), two natural proctolin analogues were present. The first one is Ala-Tyr-Leu-Pro-Thr and is designed as Ala1-proctolin. The threshold concentration for biological activity of Ala1-proctolin was 10(-7) M, compared to 10(-10) M for proctolin itself. Ala1-proctolin is the first identified biological analogue of proctolin. The full nature of the first amino acid of a third proctolin-analogue (x-Tyr-Leu-Pro-Thr) is probably a modified amino acid of which the identity could as yet not be revealed. Our results suggest the existence of a family of proctolin-like peptides.

Expression in mouse embryos and in adult mouse brain of three members of the amyloid precursor protein family, of the alpha-2-macroglobulin receptor/low density lipoprotein receptor-related protein and of its ligands apolipoprotein E, lipoprotein lipase, alpha-2-macroglobulin and the 40,000 molecular weight receptor-associated protein

We have analysed by northern blotting and by in situ hybridization the expression patterns of eight different genes during the second half of mouse embryonic development and in adult mouse brain: we compared the messenger RNA levels of amyloid precursor protein and of the two amyloid precursor protein-like proteins 1 and 2 and we have analysed expression of apolipoprotein E and of its main receptor in brain, the alpha-2-macroglobulin/low density lipoprotein receptor-related protein and three other ligands: the proteinase inhibitor alpha-2-macroglobulin, the modifying enzyme lipoprotein lipase and the 44,000 molecular weight heparin binding protein, a ligand of unknown function. During embryogenesis the temporal expression pattern differs considerably for the three members of the amyloid precursor proteins. Total embryo messenger RNA levels of amyloid precursor protein and amyloid precursor protein-like protein 2 increased progressively, while amyloid precursor protein-like protein 1 messenger RNA showed a burst of synthesis between days 10 and 13 post-coitum. Significantly, expression of the alpha-2-macroglobulin/low density lipoprotein receptor-related protein and of its associated protein, the 44,000 molecular weight heparin binding protein, exhibited their most important increase very similar to that of amyloid precursor protein-like protein 1, between days 10 and 13 post-coitum. Apolipoprotein E, lipoprotein lipase and alpha-2-macroglobulin messenger RNA levels in total embryos increased progressively, beginning most pronounced at days 13, 15 and 17, respectively. In mouse embryos, in situ hybridization established amyloid precursor protein, amyloid precursor protein-like protein 2 and alpha-2-macroglobulin/low density lipoprotein receptor-related protein messenger RNA to be expressed in most organs, with the notable exception of the liver, while expression of the other studied proteins was much more restricted. Among adult mouse tissues, the genes investigated were expressed very prominently in brain, except for lipoprotein lipase and for the complete absence of alpha-2-macroglobulin messenger RNA. In adult mouse brain, the cortex and hippocampus exhibited strong signals for most genes analysed. Exceptions are lipoprotein lipase and apolipoprotein E messenger RNAs, and the absent alpha-2-macroglobulin messenger RNA. Several interesting features, similarities as well as differences, between brain tissue sections hybridized with probes for amyloid precursor protein, amyloid precursor protein-like proteins 1 and 2 and between alpha-2-macroglobulin/low density lipoprotein receptor-related protein and heparin binding protein-44 were observed and are described. The results are further discussed in view of the known or anticipated physiological functions of the proteins examined and of their possible role in the etiology of Alzheimer's disease.

The major tuber storage protein of araceae species is a lectin. Characterization and molecular cloning of the lectin from Arum maculatum L

A new lectin was purified from tubers of Arum maculatum L. by affinity chromatography on immobilized asialofetuin. Although this lectin is also retained on mannose-Sepharose 4B, under the appropriate conditions free mannose is a poor inhibitor of its agglutination activity. Pure preparations of the Arum lectin apparently yielded a single polypeptide band of approximately 12 kD upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, N-terminal sequencing of the purified protein combined with molecular cloning of the lectin have shown that the lectin is composed of two different 12-kD lectin subunits that are synthesized on a single large precursor translated from an mRNA of approximately 1400 nucleotides. Lectins with similar properties were also isolated from the Araceae species Colocasia esculenta (L.) Schott, Xanthosoma sagittifolium (L.) Schott, and Dieffenbachia sequina Schott. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration of the different Araceae lectins have shown that they are tetrameric proteins composed of lectin subunits of 12 to 14 kD. Interestingly, these lectins are the most prominent proteins in the tuber tissue. Evidence is presented that a previously described major storage protein of Colocasia tubers corresponds to the lectin.

Amyloid precursor protein accumulation in Lewy body dementia and Alzheimer's disease

The presence of amyloid precursor protein (APP) and beta-amyloid protein (beta A4) was investigated in the cerebra of 4 patients with Alzheimer's disease (AD), 1 patient with Down's syndrome, 4 patients with dementia of the Lewy body type (DLB) and 4 age-matched, clinically nondemented controls, of which one displayed many amyloid plaques. The different types of amyloid plaques stained strongly with antibodies against beta A4. Antibodies against the C-terminal region of APP reacted only weakly with small swollen neurites and with globular deposits in neuritic-type plaques from patients with AD. The antibody against the N-terminal region of APP stained strongly cellular elements in the neuritic type plaques of patients with AD but not dense cored plaques. In contrast, patients with DLB displayed with this antibody a homogeneous staining of dense cored amyloid plaques. Some Lewy bodies stained with the antibody against the N-terminal region of APP as well. These results indicate that the processing of APP in AD and DLB could be different, to yield different fragments deposited in AD and DLB amyloid plaques.

The bark of Robinia pseudoacacia contains a complex mixture of lectins. Characterization of the proteins and the cDNA clones

Two lectins were isolated from the inner bark of Robinia pseudoacacia (black locust). The first (and major) lectin (called RPbAI) is composed of five isolectins that originate from the association of 31.5- and 29-kD polypeptides into tetramers. In contrast, the second (minor) lectin (called RPbAII) is a hometetramer composed of 26-kD subunits. The cDNA clones encoding the polypeptides of RPbAI and RPbAII were isolated and their sequences determined. Apparently all three polypeptides are translated from mRNAs of approximately 1.2 kb. Alignment of the deduced amino acid sequences of the different clones indicates that the 31.5- and 29-kD RPbAI polypeptides show approximately 80% sequence identity and are homologous to the previously reported legume seed lectins, whereas the 26-kD RPbAII polypeptide shows only 33% sequence identity to the previously described legume lectins. Modeling the 31.5-kD subunit of RPbAI predicts that its three-dimensional structure is strongly related to the three-dimensional models that have been determined thus far for a few legume lectins. Southern blot analysis of genomic DNA isolated from Robinia has revealed that the Robinia bark lectins are the result of the expression of a small family of lectin genes.

Basolateral secretion of amyloid precursor protein in Madin-Darby canine kidney cells is disturbed by alterations of intracellular pH and by introducing a mutation associated with familial Alzheimer's disease

The analysis of potential sorting signals in amyloid precursor protein (APP) by site-directed mutagenesis and the disturbance of metabolic pathways by drugs is used here to define the parameters that determine polarized secretion of APP in Madin-Darby canine kidney cells. Endogenously produced APP751/770 and APP695 produced from transfected constructs are secreted almost exclusively into the basolateral compartment. The sorting mechanism is highly dependent on intracellular pH as demonstrated by its sensitivity to primary amines and inhibitors of the acidifying vacuolar protein ATPase. The role of potential basolateral sorting signals in the cytoplasmic, transmembrane, and beta A4 amyloid region of APP was investigated. Neither deletion of the endocytosis and putative basolateral sorting signal GY.NPTY nor complete deletion of the cytoplasmic domain causes apical secretion of soluble APP. Further deletion of the transmembrane domain and of the beta A4 amyloid region confirmed that the major basolateral sorting determinant resides in the extracellular domain of APP. Increased beta-secretase cleavage of APP after introduction of the "swedish" double mutation causes apical missorting of about 20% of beta-secretase-cleaved APP. The data underline the complexity of processing and sorting APP in polarized cells and suggest a possible problem of protein sorting in Alzheimer's Disease.

Cloning, characterization, and chromosomal localization to 4p16 of the human gene (LRPAP1) coding for the alpha 2-macroglobulin receptor-associated protein and structural comparison with the murine gene coding for the 44-kDa heparin-binding protein

We report the molecular cloning of the human gene (symbol LRPAP1) coding for the alpha 2-macroglobulin receptor-associated protein (A2MRAP), as well as the gene coding for the 44-kDa heparin-binding protein (HBP-44), its murine counterpart. For both, genomic cosmid clones were isolated, and for the human gene a bacteriophage P1 clone containing the entire A2MRAP gene was also retrieved. The genes were characterized after subcloning: in both species, the known coding part of the cDNA is encoded by eight exons, and the position of the boundaries of the exons was conserved. The human LRPAP1 locus was assigned to chromosome 4 by PCR of human-hamster hybrid cell lines and by fluorescence in situ hybridization to band 4p16.3. This maps closely to the variable constitutional deletions of the short arm of chromosome 4, observed cytogenetically in patients with the Wolf-Hirschhorn syndrome. Metaphase spreads of two such patients were analyzed by fluorescence in situ hybridization with an LRPAP1 genomic probe. The first patient, with karyotype 46,XY,del4(p14-p16.1), had retained both copies of the LRPAP1 gene. In contrast, the other patient, with karyotype 46,XY,del4(p15.3-pter), displayed no signal for LRPAP1 on the deleted chromosome.

Amyloid precursor protein is not processed by furin, PACE 4, PC1/3, PC2, PC4 and PC5/6 of the furin family of proprotein processing enzymes

Proteolytic cleavage of the amyloid precursor protein (APP) has previously been shown to release its extracellular domain into the medium. The identification of the responsible proteinase(s), termed secretase(s), is a high priority in ongoing Alzheimer research. This is hampered by the unusual characteristics of these enzyme(s) and by the fact that they cleave only membrane associated APP. We report here, using a vaccinia virus based expression system, that pig kidney PK(15) cells express full-length, membrane bound APP695, but that secretion of APP is low. This heterologous expression system allows to assay candidate secretases in a cellular context by simple co-transfection of the APP and candidate secretase cDNA containing plasmids. Eight different members of the mouse and human furin family of proprotein processing enzymes were tested in this assay, but none of them enhanced the secretion of APP. Secretion of von Willebrand's factor was used as a positive control.

Identification, characterization, and immunological localization of a novel myotropic neuropeptide in the Colorado potato beetle, Leptinotarsa decemlineata

A novel myotropic heptapeptide was isolated from an extract of 54,000 heads of adult Leptinotarsa decemlineata by means of high performance liquid chromatography (HPLC), using the Locusta migratoria oviduct motility bioassay as monitoring system. The full primary structure was established as H-Ala-Tyr-Asn-Gly-Pro-Leu-Ala-NH2. This peptide, designated as Led-MNP-I, has a unique structure and does not belong to any known vertebrate or invertebrate peptide family. Two adjacent Led-MNP-I-immunoreactive perikarya were found in each optic lobe and in each half of all thoracic ganglia. Its absence from the pars intercerebralis and neurohemal organs suggests that Led-MNP-I is not a neurohormone but a neurotransmitter or neuromodulator. Treatment of isolated oviducts with varying concentrations of Led-MNP-I did not elicit significant changes in the level of cAMP concentration, suggesting that cAMP does not act as a second messenger for Led-MNP-I. Instead, Led-MNP-I induces an elevation of IP3. Treatment with Led-MNP-I did not stimulate cAMP production in the Colorado beetle brain, but this could be due to the very small number of receptive cells present. Both tissues contained a forskolin-sensitive adenylate cyclase enzyme.

Structure of the gene (LRP1) coding for the human alpha 2-macroglobulin receptor lipoprotein receptor-related protein

The alpha 2-macroglobulin receptor or lipoprotein receptor-related protein (A2MR/LRP) is an amazingly large and multifunctional receptor. The active receptor protein is derived from a 600-kDa precursor, encoded by a 15-kb mRNA, cloned and sequenced in human, mouse, and chicken. We report here the cloning of the entire human gene (LRP1) coding for A2MR/LRP. The gene covered about 92 kb and a total of 89 exons were identified, varying in size from 65 bases (exon 86) to 925 bases (exon 89). The introns varied from 82 bases (intron 53) to about 8 kb (intron 6). In the introns, 3 complete and 4 partial Alu sequences were identified. In intron 44 a complex repetitive sequence posed a cloning problem since it was not retrieved from any genomic library screened. Interexon PCR from exon 43 to 45 yielded a fragment of 2.5 kb. Attempts to subclone this fragment yielded inserts ranging between 0.8 and 1.6 kb. Sequencing of 3 subclones with different-size inserts revealed a complex repetitive element with a different size in each subclone. In the mouse LRP gene this intron was much smaller, and no repetitive sequence was observed. In 18 unrelated individuals no difference in size was observed when analyzed by interexon PCR.

Mild phenotype and normal gonadal function in females with 4p trisomy due to unbalanced t(X;4)(p22.1;p14)

In this report we describe the mild phenotypic manifestations and normal gonadal function in a 50-year-old mother and her 17-year-old daughter with 4p trisomy resulting from an unbalanced t(X;4)(p22.1;p14) mat. Late replication of the der(X) was demonstrated by BrdU incorporation with spreading of the late replication to the 4p portion as an explanation of the reduced effect of the trisomy 4p/monosomy Xp on the physical and secondary sexual development in both patients.