Tandem dup (1p) within the short arm of chromosome 1 in a child with ambiguous genitalia and multiple congenital anomalies

Mammalian tumor-like organs. 2. Mammalian adipose has many tumor features and obesity is a tumor-like process

BACKGROUND

In previous publications, the author developed the theory of carcino-evo-devo, which predicts that evolutionarily novel organs should recapitulate some features of tumors in their development.

MAIN TEXT

Mammalian adipose is currently recognized as a multi-depot metabolic and endocrine organ consisting of several adipose tissues. Although lipid-storing cells and proteins are ancient, the adipose organ as a whole is evolutionarily novel to mammals. The adipose expansion has remarkable similarities with the growth of solid tumors. These similarities are the following: (1) The capability to unlimited expansion; (2) Reversible plasticity; (3) Induction of angiogenesis; (4) Chronic inflammation; (5) Remodeling and disfunction; (6) Systemic influence on the organism; (7) Hormone production; (8) Production of miRNAs that influence other tissues; (9) Immunosuppression; (10) DNA damage and resistance to apoptosis; (11) Destructive infiltration in other organs and tissues. These similarities include the majority of "hallmarks of cancer". In addition, lipomas are the most frequent soft tissue tumors, and similar drugs may be used for the treatment of obesity and cancer by preventing infiltration. This raises the possibility that obesity, at least in part, may represent an oncological problem. The existing similarities between adipose and tumors suggest the possible evolutionary origin of mammalian adipose from some ancestral benign mesenchymal hereditary tumors. Indeed, using a transgenic inducible zebrafish tumor model, we described many genes, which originated in fish and were expressed in fish tumors. Their human orthologs LEP, NOTCH1, SPRY1, PPARG, ID2, and CIDEA acquired functions connected with the adipose organ. They are also involved in tumor development in humans.

CONCLUSION

If the hypothesis of the evolutionary origin of the adipose organ from the ancestral hereditary tumor is correct, it may open new opportunities to resolve the oncological problem and the problem of the obesity epidemic. New interventions targeting LEP, NOTCH1, SPRY1, PPARG, ID2, and CIDEA gene network, in addition to what already is going on, can be designed for treatment and prevention of both obesity and tumors.

Cloning and characterization of wnt4a gene in a natural triploid teleost, Qi river crucian carp (Carassius auratus)

WNT4 (wingless-type MMTV integration site family, member 4) plays a key role in the ovarian differentiation and development in mammals. However, the possible roles of Wnt4 during gonadal differentiation and development need further clarification in teleosts. In this study, we cloned and characterized the full-length cDNA of Qi river crucian carp (Carassius auratus) wnt4a gene (CA-wnt4a). The cDNA of CA-wnt4a is 2337 bp, including the ORF of 1059 bp, encoding a putative protein with a transmembrane domain and a WNT family domain. Sequence and phylogenetic analyses revealed that the CA-Wnt4a identified is a genuine Wnt4a. Tissue distribution analysis showed that CA-wnt4a is expressed in all the tissues examined, including ovary. CA-wnt4a undergoes a stepwise increase in the embryonic stages, suggesting that CA-wnt4a might be involved in the early developmental stage. Ontogenic analysis demonstrated that CA-wnt4a expression is upregulated in the ovaries at 30-50 days after hatching (dah), the critical period of sex determination/differentiation in Qi river crucian carp. From 90 dah, the expression of CA-wnt4a was gradually downregulated in the developing ovaries. Immunohistochemistry demonstrated that CA-Wnt4a was expressed in the somatic and germ cells of the ovary by 30 dah, thereafter, positive signals of Wnt4a were detected in the somatic cells, oogonia and primary growth oocytes from 60 dah. In the sex-reversed testis induced by letrozole treatment, the expression level of CA-wnt4a was significantly downregulated. When CA-wnt4a expression was inhibited by injection of FH535 (an inhibitor of canonical Wnt/β-catenin signal pathway) in the ovaries, levels of cyp19a1a, foxl2 mRNA were significantly downregulated, while sox9b and cyp11c1 were upregulated, which suggested that together with Foxl2-leading estrogen pathway, CA-wnt4a signaling pathway might be involved in ovarian differentiation and repression of the male pathway gene expression in Qi river crucian carp.

Sex determination and maintenance: the role of DMRT1 and FOXL2

In many species, including mammals, sex determination is genetically based. The sex chromosomes that individuals carry determine sex identity. Although the genetic base of phenotypic sex is determined at the moment of fertilization, the development of testes or ovaries in the bipotential early gonads takes place during embryogenesis. During development, sex determination depends upon very few critical genes. When one of these key genes functions inappropriately, sex reversal may happen. Consequently, an individual's sex phenotype may not necessarily be consistent with the sex chromosomes that are present. For some time, it has been assumed that once the fetal choice is made between male and female in mammals, the gonadal sex identity of an individual remains stable. However, recent studies in mice have provided evidence that it is possible for the gonadal sex phenotype to be switched even in adulthood. These studies have shown that two key genes, doublesex and mad-3 related transcription factor 1 (Dmrt1) and forkhead box L2 (Foxl2), function in a Yin and Yang relationship to maintain the fates of testes or ovaries in adult mammals, and that mutations in either gene might have a dramatic effect on gonadal phenotype. Thus, adult gonad maintenance in addition to fetal sex determination may both be important for the fertility.

Cloning and characterization of wnt4a gene and evidence for positive selection in half-smooth tongue sole (Cynoglossus semilaevis)

Wnt4 gene plays a role in developmental processes in mammals. However, little is known regarding its function in teleosts. We cloned and characterized the full-length half-smooth tongue sole (Cynoglossus semilaevis) wnt4a gene (CS-wnt4a). CS-wnt4a cDNA was 1746 bp in length encoding 353aa. CS-wnt4a expression level was highest in the testis, and gradually increased in the developing gonads until 1 year of age. In situ hybridization revealed that CS-wnt4a expression level was highest in stage II oocytes and sperm in the adult ovary and testis, respectively. CS-wnt4a expression level was significantly up-regulated in the gonads after exposure to high temperature. The level of methylation of the CS-wnt4a first exon was negatively correlated with the expression of CS-wnt4a. The branch-site model suggested that vertebrate wnt4a differed significantly from that of wnt4b, and that the selective pressures differed between ancestral aquatic and terrestrial organisms. Two positively selected sites were found in the ancestral lineages of teleost fish, but none in the ancestral lineages of mammals. One positively selected site was located on the α-helices of the 3D structure, the other on the random coil. Our results are of value for further study of the function of wnt4 and the mechanism of selection.

Genetic control of ovarian development

During embryonic development, ovarian somatic cells embark on a course that is separate from male somatic cells and from indifferent precursor cells. While the former aspect of ovarian development is well known, the latter has not received much attention until recently. This review attempts to integrate the most recent work regarding the differentiation of ovarian somatic cells. The discussion of the parallel development of the testis is limited to the key differences only. Similarly, germ cell development will be introduced only inasmuch as it becomes necessary to draw attention to a particular aspect of the somatic component differentiation. Finally, while postnatal ovarian development and folliculogenesis undoubtedly provide the ultimate morphological and functional fitness tests for the ovarian somatic cells, postnatal phenotypes will be only referred to when they have already been connected to genes that are expressed during embryogenesis.

The molecular and cellular basis of gonadal sex reversal in mice and humans

The mammalian gonad is adapted for the production of germ cells and is an endocrine gland that controls sexual maturation and fertility. Gonadal sex reversal, namely, the development of ovaries in an XY individual or testes in an XX, has fascinated biologists for decades. The phenomenon suggests the existence of genetic suppressors of the male and female developmental pathways and molecular genetic studies, particularly in the mouse, have revealed controlled antagonism at the core of mammalian sex determination. Both testis and ovary determination represent design solutions to a number of problems: how to generate cells with the right properties to populate the organ primordium; how to produce distinct organs from an initially bipotential primordium; how to pattern an organ when the expression of key cell fate determinants is initiated only in a discrete region of the primordium and extends to other regions asynchronously; how to coordinate the interaction between distinct cell types in time and space and stabilize the resulting morphology; and how to maintain the differentiated state of the organ throughout the adult period. Some of these, and related problems, are common to organogenesis in general; some are distinctive to gonad development. In this review, we discuss recent studies of the molecular and cellular events underlying testis and ovary development, with an emphasis on the phenomenon of gonadal sex reversal and its causes in mice and humans. Finally, we discuss sex-determining loci and disorders of sex development in humans and the future of research in this important area. WIREs Dev Biol 2012, 1:559–577. doi: 10.1002/wdev.42

GATA transcription factors in the developing reproductive system

Previous work has firmly established the role for both GATA4 and FOG2 in the initial global commitment to sexual fate, but their (joint or individual) function in subsequent steps remained unknown. Hence, gonad-specific deletions of these genes in mice were required to reveal their roles in sexual development and gene regulation. The development of tissue-specific Cre lines allowed for substantial advances in the understanding of the function of GATA proteins in sex determination, gonadal differentiation and reproductive development in mice. Here we summarize the recent work that examined the requirement of GATA4 and FOG2 proteins at several critical stages in testis and ovarian differentiation. We also discuss the molecular mechanisms involved in this regulation through the control of Dmrt1 gene expression in the testis and the canonical Wnt/ß-catenin pathway in the ovary.

Genetic mechanisms underlying male sex determination in mammals

Genetic control of gonadal development proceeds through either the male or female molecular pathways, driving bipotential gonadal anlage differentiation into a testis or ovary. Antagonistic interactions between the 2 pathways determine the gonadal sex. Essentially sex determination is the enhancement of one of the 2 pathways according to genetic sex. Initially, Sry with other factors upregulates Sox9 expression in XY individuals. Afterwards the expression of Sox9 is maintained by a positive feedback loop with Fgf9 and prostaglandin D2 as well as by autoregulative ability of Sox9. If these factors reach high concentrations, then Sox9 and/or Fgf9 may inhibit the female pathway. Surprisingly, splicing, nuclear transport, and extramatrix proteins may be involved in sex determination. The male sex determination pathway switches on the expression of genes driving Sertoli cell differentiation. Sertoli cells orchestrate testicular differentiation. In the absence of Sry, the predomination of the female pathway results in the realization of a robust genetic program that drives ovarian differentiation.

A 649 kb microduplication in 1p34.1, including POMGNT1, in a patient with microcephaly, coloboma and laryngomalacia; and a review of the literature

We report on a male patient with intra-uterine growth retardation, microcephaly, coloboma, laryngomalacia and developmental delay. Array CGH analysis revealed a 649 kb duplication on chromosome 1p34.1. Only five patients with overlapping duplications have been reported thus far. Ten known genes are located in the duplicated region, including the POMGNT1 gene encoding for O-mannose beta-1,2-N-acetylglucosaminyltransferase. This gene, mutated in muscle-eye-brain disease, might be causative for the observed phenotype in our patient.

Global survey of protein expression during gonadal sex determination in mice

The development of an embryo as male or female depends on differentiation of the gonads as either testes or ovaries. A number of genes are known to be important for gonadal differentiation, but our understanding of the regulatory networks underpinning sex determination remains fragmentary. To advance our understanding of sexual development beyond the transcriptome level, we performed the first global survey of the mouse gonad proteome at the time of sex determination by using two-dimensional nanoflow LC-MS/MS. The resulting data set contains a total of 1037 gene products (154 non-redundant and 883 redundant proteins) identified from 620 peptides. Functional classification and biological network construction suggested that the identified proteins primarily serve in RNA post-transcriptional modification and trafficking, protein synthesis and folding, and post-translational modification. The data set contains potential novel regulators of gonad development and sex determination not revealed previously by transcriptomics and proteomics studies and more than 60 proteins with potential links to human disorders of sexual development.

Array comparative genomic hybridisation-based identification of two imbalances of chromosome 1p in a 9-year-old girl with a monosomy 1p36 related phenotype and a family history of learning difficulties: a case report

INTRODUCTION

Monosomy 1p36 is one of the most common terminal deletion syndromes, with an approximate incidence of 1 in every 5000 live births. This syndrome is associated with several pronounced clinical features including characteristic facial features, cardiac abnormalities, seizures and mental retardation, all of which are believed to be due to haploinsufficiency of genes within the 1p36 region. The deletion size varies from approximately 1.5 Mb to 10 Mb with the most common breakpoints located at 1p36.13 to 1p36.33. Over 70% of 1p36 deletion patients have a true terminal deletion. A further 7% have interstitial deletions and a proportion have a derivative chromosome 1 where the 1p telomere is replaced by material from another chromosome, either as a result of a de-novo rearrangement or as a consequence of malsegregation of a balanced parental translocation at meiosis.

CASE PRESENTATION

Array comparative genomic hybridisation analysis of a 9-year-old Caucasian girl presenting with dysmorphic facial features and learning difficulties, for whom previous routine karyotyping had been normal, identified two submicroscopic rearrangements within chromosome 1p. Detection of both an insertional duplication of a region of 1p32.3 into the subtelomeric region of the short arm of a chromosome 1 homologue and a deletion within 1p36.32 of the same chromosome instigated a search for candidate genes within these regions which could be responsible for the clinical phenotype of the patient. Several genes were identified by computer-based annotation, some of which have implications in neurological and physical development.

CONCLUSION

Array comparative genomic hybridisation is providing a robust method for pinpointing regions of candidate genes associated with clinical phenotypes that extend beyond the resolution of the light microscope. This case report provides an example of how this method of analysis and the subsequent reporting of findings have proven useful in collaborative efforts to elucidate multiple gene functions from a clinical perspective.

Wnt4 action in gonadal development and sex determination

Wnt4 is a growth factor involved in multiple developmental processes such as the formation of the kidney, adrenal, mammary gland, pituitary and the female reproductive system. During mammalian embryogenesis, Wnt4 is expressed in the gonads of both sexes before sex determination events take place and is subsequently down-regulated in the male gonad. Inactivation of the Wnt4 gene in mice has revealed that it is involved at several steps of female reproductive development. Wnt4 is implicated in Müllerian duct regression, the formation of sex-specific vasculature, the inhibition of steroidogenesis and in sex-specific cell migration events. A mouse model of sex-reversal has partially unravelled the molecular pathways in which Wnt4 operates during the development of the female reproductive system. However, the specific molecular mechanism of action of Wnt4 during gonadal development remains unknown. This and downstream signaling pathways involved in Wnt4 action during female gonad development are reviewed and models of Wnt4 action are proposed for Müllerian duct formation, sex-specific vasculature development, and sex determination events. Further identification of critical downstream effectors of the Wnt4 signaling pathway in mouse models and in patients with sex-reversal conditions could help in understanding sex-reversal pathologies in humans.

A novel 8.5 MB dup(1)(p34.1p34.3) characterized by FISH in a child presenting with congenital heart defect and dysmorphic features

Chromosome duplications involving 1p are rarely reported but are apparently associated with short survival as well as congenital malformations and impaired development. Several of these have had congenital heart defects, although too few patients have been reported with similar breakpoints to characterize a syndrome. We present a girl with a novel interstitial duplication in the short arm of chromosome 1 [46,XX,dup(1)(p34.1p34.3)]. She presented with congenital heart defects at 1 month and by 1 year of age manifested delayed acquisition of motor milestones and subsequently of language milestones. By breakpoint-mapping using FISH analysis, we determined that her 1p duplication spans 8.5 megabases. Her 1p duplication is the smallest reported to date to contain 1p34 in patients with congenital heart defect due to abnormalities of heart looping during development. Thus, her 8.5 MB duplication provides a target region to search for a potentially dosage-sensitive gene(s) causing abnormal heart looping when duplicated. Two patients have been reported with duplication including 1p34 but without congenital heart defect, and their duplications span all but the distal approximately 2 MB segment duplicated in our patient. Thus, within our patient's 8.5 MB target region for a dosage sensitive gene leading to looping abnormalities (and thereby congenital heart defect), the distal 2 MB region might well be the region to begin the search.

Partial trisomy 1p due to paternal t(1;9) translocation in a family with recurrent miscarriages

OBJECTIVE

To report a new case with partial trisomy 1p due to paternal t(1;9) translocation in a family with recurrent miscarriages.

DESIGN

Case report.

SETTING

Faculty of Medicine, Cukurova University.

PATIENT(S)

A couple with recurrent miscarriages, an abnormal fetus, a newborn infant, paternal grandfather and grandmother.

INTERVENTION(S)

Chorionic villi sampling (CVS), amniocentesis, lymphocytic karyotype, and genetic counseling.

MAIN OUTCOME MEASURE(S)

Chromosomal analysis of CVS, amniotic cells, and peripheral blood lymphocytes were performed according to standard cytogenetic methods using G-banding technique.

RESULT(S)

We determined the reproductive risk in a couple who carried a balance and an unbalanced rearrangement of chromosomes 1 and 9 in two generations of a normal father with derivative 9 karyotype. The prenatal and postnatal karyotypes of the newborn infant were the same as the father [46,XY,der(9)t(1:9)(p34.2;q34.3)]. He was also phenotypically normal. The abnormal fetus that was miscarried also had a derivative 9 [46,XY,der(9)t(1:9)(p34.2;q34.3)fat]. The der(9) contained the partial short arm of chromosome 1. Both chromosome 1 showed normal. Trisomy 1p in the fetus was the result of familial derivative 9.

CONCLUSION(S)

Partial trisomy is associated with fetal wastage, and may play a role in the etiology of the other miscarriages in certain families. The apparent lack of increased reproductive failure may result from the selective disadvantage of aneusomic gamets at fertilization or very early spontaneous abortions of unbalanced conceptuses. The detection of couples with chromosomal anomalies can undoubtedly help prevent the births of malformed infants. These findings would be used widely in clinical genetics and as an effective tool for genetic counseling and reproductive guidance.

Three cases with rare interstitial rearrangements of chromosome 1 characterized by multicolor banding

In this report, we describe three unrelated patients with similar symptoms such as mental retardation, growth delay and multiple phenotypic abnormalities. GTG-banding analysis revealed karyotypes with add(1p) in two cases and an add(1q) in the third. Fluorescence in situ hybridization (FISH) analysis using high resolution multicolor banding (MCB) characterized the aberrations of the abnormal chromosomes 1 as a (sub)terminal duplication and inverted duplications, respectively. Although three different chromosomal regions i.e. 1p36.1, 1p36.2-->1p31.3 and 1q41-->1q44 were involved, all three patients had similar patterns of dysmorphic findings. These cases demonstrate the power of MCB in the characterization of small interstitial chromosomal aberrations and resulted in the characterization of three previously unreported congenital chromosome 1 rearrangements.

The endless quest for sex determination genes

Disorders in human sex determination cause defects in gonadal function and can result in a spectrum of abnormalities in the internal and external genitalia, ranging from relatively mild sexual ambiguities to complete sex reversal. Several genes involved in sex determination have been validated in humans, and activities of their gene products are being elucidated, particularly in mouse models. However, how these genes interact in an overall process remains far from clear, and it is probable that many additional genes are involved. Management of patients with pathologies in sex determination and subsequent differentiation is currently under debate, but will require not only an understanding of the multiple definitions of an individual's sex but also an increased knowledge of the molecular mechanisms involved in sex determination.

DAX1 and its network partners: exploring complexity in development

DAX1 encoded by NR0B1, when mutated, is responsible for X-linked adrenal hypoplasia congenita (AHC). AHC is due to failure of the adrenal cortex to develop normally and is fatal if untreated. When duplicated, this gene is associated with an XY sex-reversed phenotype. DAX1 expression is present during development of the steroidogenic hypothalamic-pituitary-adrenal-gonadal (HPAG) axis and persists into adult life. Despite recognition of the crucial role for DAX1, its function remains largely undefined. The phenotypes of patients and animal models are complex and not always in agreement. Investigations using cell lines have proved difficult to interpret, possibly reflecting cell line choices and their limited characterization. We will review the efforts of our group and others to identify appropriate cell lines for optimizing ex vivo analysis of NR0B1 function throughout development. We will examine the role of DAX1 and its network partners in development of the hypothalamic-pituitary-adrenal/gonadal axis (HPAG) using a variety of different types of investigations, including those in model organisms. This network analysis will help us to understand normal and abnormal development of the HPAG. In addition, these studies permit identification of candidate genes for human inborn errors of HPAG development.

Dax-1 (dosage-sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome, gene 1) gene transcription is regulated by wnt4 in the female developing gonad

Dax-1 [dosage-sensitive sex reversal-adrenal hypoplasia congenita critical region on the X chromosome, gene 1 (NR0B1)] is an orphan nuclear receptor acting as a suppressor of Ad4 binding protein/steroidogenic factor 1 [Ad4BP/SF-1 (NR5A1)] and as an anti-Sry factor in the process of gonadal sex differentiation. The roles of these nuclear receptors in the differentiation of the gonads and the adrenal cortex have been established through studies of the mutant phenotype in both mice and humans. However, the mechanisms underlying transcriptional regulation of these genes remain largely unknown. Here, we examined the relationship between Dax-1 gene transcription and the Wnt4 pathway. Reporter gene analysis revealed that Dax-1 gene transcription was activated by beta-catenin, a key signal-transducing protein in the Wnt pathway, acting in synergy with Ad4BP/SF-1. Interaction between beta-catenin and Ad4BP/SF-1 was observed using yeast two-hybrid and in vitro pull-down assays. The region of Ad4BP/SF-1 essential for this interaction consists of an acidic amino acid cluster, which resides in the first helix of the ligand-binding domain. Mutation of the amino acid cluster impaired transcriptional activation of Dax-1 as well as interaction of Ad4BP/SF-1 with beta-catenin. These results were supported by in vivo observations using Wnt4 gene-disrupted mice, in which Dax-1 gene expression was decreased significantly in sexually differentiating female gonads. We thus conclude that Wnt4 signaling mediates the increased expression of Dax-1 as the ovary becomes sexually differentiated.

Interstitial duplication of the short arm of chromosome 1 in a newborn with congenital heart disease and multiple malformations

Interstitial duplications of chromosomes 1p are rare, with only 14 cases previously reported in the literature, and those have not revealed a unique syndrome. The phenotypes include multiple congenital abnormalities and both intra- and extra-uterine growth retardation. In general, the patients do poorly and do not survive beyond the age of several months. We report a newborn male with karyotype 46, XY, inv dup(1)(qter--> p34.3::p34.3-->p32.3::34.3-->pter) with multiple congenital abnormalities including congenital heart disease and co-existing portal and pulmonary hypertension. The chromosome 1 origin of the extra material was confirmed with fluorescent in situ hybridization (FISH). Review of the GDB [Human Genome Database, 1990] reveals that the duplicated region includes the locus EDN2 that encodes endothelin-1, a potent vasoconstrictor, making genetic overdosage of this protein a likely etiology of the pulmonary hypertension. The diffuse abnormalities show effects in multiple cell lines and suggest that this region of chromosome 1p could be involved in determining cell migration and/or differentiation during organogenesis.

Up-regulation of WNT-4 signaling and dosage-sensitive sex reversal in humans

Wnt-4, a member of the Wnt family of locally acting secreted growth factors, is the first signaling molecule shown to influence the sex-determination cascade. In mice, a targeted deletion of Wnt-4 causes the masculinization of XX pups. Therefore, WNT-4, the human homologue of murine Wnt-4, is a strong candidate gene for sex-reversal phenotypes in humans. In this article, we show that, in testicular Sertoli and Leydig cells, Wnt-4 up-regulates Dax1, a gene known to antagonize the testis-determining factor, Sry. Furthermore, we elucidate a possible mechanism for human XY sex reversal associated with a 1p31-p35 duplication including WNT-4. Overexpression of WNT-4 leads to up-regulation of DAX1, which results in an XY female phenotype. Thus, WNT-4, a novel sex-determining gene, and DAX1 play a concerted role in both the control of female development and the prevention of testes formation. These observations suggest that mammalian sex determination is sensitive to dosage, at multiple steps in its pathway.

Molecular and clinical characterization of a patient with duplication of 1p36.3 and metopic synostosis

Chromosome 1p duplications are rare. There have been only 11 reported cases of isolated 1p duplication, all of which were proximal, interstitial duplications. We present a patient with a terminal duplication of 1p (1p36.3). To our knowledge, this is the first such reported case. Our patient presented with metopic synostosis, rectal stenosis, atrial septal defect, and mildly delayed gross motor development. Molecular characterization using microsatellite marker analysis and fluorescence in situ hybridization (FISH) revealed an area of duplication between p58 and D1S2893, approximately 13 cM in size. We compare our patient's clinical findings with the clinical phenotype found in patients with the corresponding deletion of 1p36.3 and discuss the role of gene dosage in other deletion/duplication syndromes.

Sex reversal in a child with the karyotype 46,XY, dup (1) (p22.3p32.3)

The karyotype 46,XY, dup(1) (p22.3p32.3) was found in a 10-year-old patient with sex reversal, mental retardation and multiple dysmorphic features. In other cases with duplication 1p but different breakpoints cryptorchidism and genital ambiguity have been observed suggesting the dosage effect of a locus in 1p involved in sex differentiation.

Familial partial duplication (1)(p21p31)

A partial duplication (1)(p21p31), resulting from a maternal direct insertion (13,1) (q22p21p31), was found in a 30-year-old woman with mental retardation, cleft palate, and multiple minor anomalies. Two other affected and deceased relatives were presumed to have the same chromosome imbalance. Duplication 1p cases are reviewed.

A presumptive translocation 1p;2q resulting in duplication 1p and deletion 2q

Here we report on a girl with a translocation between 1 and 2 and duplication 1p and deletion 2q resulting in a multiple congenital anomaly syndrome including intrauterine growth retardation, microcephaly, hypotelorism, cleft palate, subglottic stenosis, umbilical hernia, scoliosis, anal atresia, bilateral calcaneovalgus, overlapping toes, and vertebral anomalies.

Direct duplication of chromosome 1, dir dup(1)(p21.2----p32) in a Bedouin boy with multiple congenital anomalies

Here we describe a Bedouin boy with a de novo duplication of 1p and multiple congenital anomalies. He had microcephaly, convergent squint, anteverted nostrils, malformed ears, micrognathia, hypoplasia of the terminal phalanges, clinodactyly of 5th fingers, simian creases, left inguinal hernia, cryptorchidism, and severe postnatal growth retardation. Our clinical findings are compared with those of previous reports of duplication involving chromosome 1p.