Chromosome 22q11.2 microdeletion in monozygotic twins with discordant phenotype and deletion size

We report on a pair of male monozygotic twins with 22q11.2 microdeletion, discordant phenotype and discordant deletion size. The second twin had findings suggestive of DiGeorge syndrome, while the first twin had milder anomalies without any cardiac malformation. The second twin had presented with intractable convulsion, cyanosis and cardiovascular failure in the fourth week of life and expired on the sixth week of life, whereas the first twin had some characteristic facial appearance with developmental delay but no other signs of the 22q11.2 microdeletion syndrome including cardiovascular malformation. The fluorescence in situ hybridization (FISH) analysis had shown a microdeletion on the chromosome 22q11.2 in both twins. The interphase FISH did not find any evidence for the mosaicism. The genomic DNA microarray analysis, using HumanCytoSNP-12 BeadChip (Illumina), was identical between the twins except different size of deletion of 22q11.2. The zygosity using HumanCytoSNP-12 BeadChip (Illumina) microarray analysis suggested monozygosity. This observation indicates that altered size of the deletion may be the underlying etiology for the discordance in phenotype in monozygotic twins. We think early post zygotic events (mitotic non-allelic homologous recombination) could have been played a role in the alteration of 22q11.2 deletion size and, thus phenotypic variability in the monozygotic twins

Prevalence of 22q11.2 microdeletion in 146 patients with cardiac malformation in a referral hospital of North India

<p>Abstract</p> <p>Background</p> <p>The 22q11.2 microdeletion syndrome is a common condition that is associated with cardiac as well as extra-cardiac manifestations. Its prevalence and manifestations from north India has not been reported. This study was designed to determine the prevalence and ability of clinical criteria to predict 22q11.2 microdeletion.</p> <p>Methods</p> <p>A total of 146 cases of cardiac malformation requiring tertiary care at a teaching hospital were prospectively screened for 22q11.2 microdeletion using fluorescence in situ hybridization test. Detailed clinical information was obtained as per guidelines of Tobias, <it>et al </it>(1999).</p> <p>Results</p> <p>Nine out of 146 patients (6.16%) was found to have 22q11.2 microdeletion. All the positive patients showed the presence of extra-cardiac features of 22q11.2 microdeletion syndrome. None of the cases with isolated cardiac defect were positive for microdeletion.</p> <p>Conclusions</p> <p>It seems that 22q11.2 microdeletion syndrome is over-suspected in children with isolated congenital heart defects. Screening for 22q11.2 microdeletion should be considered in those cardiac malformation cases which have extra-cardiac manifestations in the form of facial dysmorphism and hypocalcaemia.</p

Placental chimerism in early human pregnancy

Background: Human chimerism is rare and usually uncovered through investigations of ambiguous genitalia or blood grouping or prenatal diagnosis. Most of the publications on placental chimerism are mainly case reports. There is no systematic search with sensitive techniques for placental chimerism in human. Aim: This study was aimed to asses placental chimerism through two sensitive molecular techniques i.e., interphase fluorescent in situ hybridization and quantitative fluorescent PCR. Material and methods: Placental chimerism was analyzed using X & Y dual color fluorescent in-situ hybridization onto 154 placentae from natural conceptions, obtained at termination of pregnancy between 7 to 16 weeks of gestation. Results: Three cases of placental sex chromosome chimerism were observed (1.95%). Exclusion of maternal contamination and diagnosis was confirmed later by quantitative fluorescent PCR. Conclusion: This finding indicates that placental chimerism in early human pregnancy is not rare

Amniotic band syndrome and/or limb body wall complex: split or lump

Ashutosh HalderDepartment of Reproductive Biology, All India Institute of Medical Sciences, New Delhi, IndiaAbstract: Six cases of amniotic band syndrome/limb body wall complex were studied in respect to clinicopathologic characteristics. The diagnosis was based on two out of three of the following manifestations: cranio facial clefts; limb body wall defects and amniotic band attachment. Four cases were stillborn and associated with internal defects, including central nervous system. Two cases had facial and limb defects and were live born (3&amp;ndash;5 years old at examination). Phenotypic features of the stillborn cases were craniofacial clefting, thoracoabdominoschisis, amputation, ring constriction, amniotic band adhesion, placental adhesions, and internal malformations. Histology of bands revealed fibroconnective tissue as well as flattened epithelial cells together with neuroectodermal elements. Umbilical cord section revealed an abnormal number of vessels. When analyzing the observed data in relation to their etiology, it was found that amniotic disruption, vascular disruption or genetic disruption could explain the amniotic band syndrome/limb body wall complexes, alone or in combinations. A brief review of literature in search of pathogenesis is offered along with an etiopathogenetic model.Keywords: amniotic band syndrome, limb body wall complex and pathogenesi

Sertoli cell only syndrome: Status of sertoli cell maturation and function

Background of the study: Mature and functional Sertoli cells are essential for the survival of germ cells in testes. In Sertoli cell only syndrome (SCOS), there is no germ cells. Then, question arises whether absence of germ cells in SCOS secondary to Sertoli cells immaturity or mal function. Sertoli cells maturational and functional status is unclear in SCOS. This study investigated status of maturation and function of Sertoli cells in patients with SCOS. Materials and Methods: The present study was comprised of 37 cases of SCOS and 50 normal control males. Detailed clinical examination and investigation were carried out as per pre-determined proforma. Semen analysis, hormonal analysis (FSH, LH, testosterone, etc.), and fine needle aspiration cytology (FNAC) of testes (bilateral) were performed. Fluorescence in situ hybridization (FISH) with XY probes was carried out in addition to conventional chromosome analysis to find out chromosomal abnormalities, in particular sex chromosome aneuploidy, including mosaicism. Yq microdeletion status was also investigated. The anti-mullerian hormone (AMH), inhibin B, and seminal lactate were estimated by ELISA methods. Results: The study did not find any case of high AMH. About 78% cases had low inhibin B, and 60% had low AMH. FSH was high in about 78% cases. Low level of lactate was found in 49% cases. There was one case of high level of inhibin B. There were 6 (16.2%) cases of chromosomal abnormality (2 mosaic Klinefelter and 4 Klinefelter syndrome) and 4 (10.8%) cases of Yq microdeletion. Conclusion: We conclude that Sertoli cell immaturity does not play any role in SCOS (no case of high AMH). It seems, in majority cases, Sertoli cells are functionally- and/or numerically-deficient (low inhibin B, AMH and lactate). However, in about 22% cases, Sertoli cell function and/or number remains normal (normal inhibin B, AMH). Inhibin B and FSH seems best predictor/marker of Sertoli cell function

Male-like external genitalia with epididymis in a case of 46, XX disorder of sex development due to congenital adrenal hyperplasia

&lt;ul&gt; &lt;li&gt;A case of five and half-year-old 46,XX phenotypic male with hyper pigmented empty scrotum, penile urethra, epididymis along with fallopian tubes, uterus and upper vagina as well as ovary is described. Hormonal studies were consistent with the diagnosis of congenital adrenal hyperplasia. The case represents the first documented case of 46,XX disorder of sex development due to virilizing CAH associated with differentiation of Wolffian ducts into epididymis.&lt;/li&gt; &lt;li&gt;&lt;strong&gt;KEY WORDS&lt;/strong&gt;: 46,XX, virilization, external genitalia, epididymis, congenital adrenal hyperplasia&lt;/li&gt; &lt;/ul&gt

Mosaic 22q11.2 microdeletion syndrome: diagnosis and clinical manifestations of two cases

Abstract Chromosome 22q11.2 microdeletion syndrome is due to microdeletion of 22q11.2 region of chromosome 22. It is a common microdeletion syndrome however mosaic cases are very rare and reported only few previous occasions. In this report we describe two unrelated male children with clinical features consistent with 22q11.2 microdeletion syndrome characterized by cardiac defect, facial dysmorphism and developmental deficiency. One of the cases also had trigonocephaly. Interphase & metaphase FISH with 22q11.2 probe demonstrated mosaicism for hemizygous deletion of 22q11.2 region. Mosaicism is also observed in buccal cells as well as urine cells. Parents were without any deletion. These two cases represent rare cases of mosaic 22q11.2 microdeletion syndrome.</p

Fluorescence in situ hybridization (FISH) using non-commercial probes in the diagnosis of clinically suspected microdeletion syndromes

Background & objectives: Microdeletion syndromes are characterized by small (<5 Mb) chromosomal deletions in which one or more genes are involved. These are frequently associated with multiple congenital anomalies. The phenotype is the result of haploinsufficiency of genes in the critical interval. Fluorescence in situ hybridization (FISH) technique is commonly used for precise genetic diagnosis of microdeletion syndromes. This study was conducted to assess the role of FISH in the diagnosis of suspected microdeletion syndrome. Methods: FISH was carried out on 301 clinically suspected microdeletion syndrome cases for the confirmation of clinical diagnosis using non-commercial probes. Of these, 177 cases were referred for 22q11.2 microdeletion, 42 cases were referred for William syndrome, 38 cases were referred for Prader Willi/Angelman and 44 cases were referred for other suspected microdeletion syndromes. Results: FISH was confirmatory in 23 cases only (7.6%). There were 17 cases of 22q11.2 microdeletion, four cases of Prader Willi syndrome and two cases of William syndrome. Interpretation & conclusion: We conclude that FISH should not be the method of choice for clinically suspected microdeletion syndromes. We propose to follow strict clinical criteria for FISH testing or preferably to follow better methods (genotype first approach). Whole genome screening may be used as first line of test and FISH may be used for confirmation of screening result, screening of family members and prenatal diagnosis