Phelan McDermid Syndrome: Multiple Sclerosis as a Rare but Treatable Cause for Regression-A Case Report.

Phelan McDermid syndrome (PMcD) is a neurogenetic disease associated with haploinsufficiency of the SHANK3 gene due to a spectrum of anomalies in the terminal region of the long arm of chromosome 22. SHANK3 is the abbreviation for SH3 domain and ankyrin repeat-containing protein, a gene that encodes for proteins of the postsynaptic density (PSD) of excitatory synapses. This PSD is relevant for the induction and plasticity of spine and synapse formation as a basis for learning processes and long-term potentiation. Individuals with PMcD present with intellectual disability, muscular hypotonia, and severely delayed or absent speech. Further neuropsychiatric manifestations cover symptoms of the autism spectrum, epilepsy, bipolar disorders, schizophrenia, and regression. Regression is one of the most feared syndromes by relatives of PMcD patients. Current scientific evidence indicates that the onset of regression is variable and affects language, motor skills, activities of daily living and cognition. In the case of regression, patients normally undergo further diagnostics to exclude treatable reasons such as complex-focal seizures or psychiatric comorbidities. Here, we report, for the first time, the case of a young female who developed progressive symptoms of regression and a dystonic-spastic hemiparesis that could be traced back to a comorbid multiple sclerosis and that improved after treatment with methylprednisolone.

Síndrome de Phelan-McDermid: un caso clínico con una deleción de 1, 7 Mb en 22q13.3 / Phelan-McDermid syndrome: a case with a 1.7 Mb deletion in 22q13.3

Introducción: El síndrome de Phelan-McDermid está producido por una microdeleción en la región 22q13.3. Esta microdeleción se ve asociada a una gran variabilidad fenotípica, y recientemente se ha sugerido una correlación entre el tamaño de la deleción y la gravedad de la sintomatología. Caso clínico: En el presente trabajo describimos el caso clínico de un niño atendido en nuestro hospital con un importante retraso en el área del lenguaje y el aprendizaje, en el que se realizó un análisis genético mediante MLPA (multiplex ligation-dependent probe amplification) y microarray. Resultados: Se detectó en el paciente una deleción terminal de 1,7 Mb en el cromosoma 22 con una pérdida de los genes ARSA-1, SHANK3 y RABL2B. Conclusión: El análisis de las microdeleciones en el cromosoma 22q13.3 mediante la técnica de microarray permite determinar qué genes están afectados en los casos de síndrome de Phelan-McDermid, y establecer una mejor correlación genotipo-fenotipo para predecir la evolución de cada paciente de una forma más precisa (AU)

Introduction: Phelan-McDermid syndrome is caused by a microdeletion in the 22q13.3 region that has been related to high phenotypic variability. Recently, it has been suggested a correlation between the size of the deletion and the severity of the symptoms presented by patients. Case report: We report the case of a child treated at our Hospital with a significant delay in the area of language and learning, and the results of the genetic analysis performed using multiplex ligation-dependent probe amplification (MLPA) and microarray techniques. Results: A 1.7 Mb terminal deletion was detected on chromosome 22 with a loss of ARSA-1, SHANK3 and RABL2B genes. Conclusion: Microdeletion analysis of 22q13.3 region should be performed by microarray technique in order to detect which genes are involved in Phelan-McDermid syndrome, finding a better phenotype-genotype correlation that will allow predicting patient’s prognosis more accurately (AU)

False Negative NIPT Results: Risk Figures for Chromosomes 13, 18 and 21 Based on Chorionic Villi Results in 5967 Cases and Literature Review.

Non-invasive prenatal testing (NIPT) demonstrated a small chance for a false negative result. Since the "fetal" DNA in maternal blood originates from the cytotrophoblast of chorionic villi (CV), some false negative results will have a biological origin. Based on our experience with cytogenetic studies of CV, we tried to estimate this risk. 5967 CV samples of pregnancies at high risk for common aneuplodies were cytogenetically investigated in our centre between January 2000 and December 2011. All cases of fetal trisomy 13, 18 and 21 were retrospectively studied for the presence of a normal karyotype or mosaicism < 30% in short-term cultured (STC-) villi. 404 cases of trisomies 13, 18 and 21 were found amongst 5967 samples (6,8%). Of these 404 cases, 14 (3,7%) had a normal or low mosaic karyotype in STC-villi and therefore would potentially be missed with NIPT. It involved 2% (5/242) of all trisomy 21 cases and 7.3% (9/123) of all trisomy 18 cases. In 1:426 (14/5967) NIPT samples of patients at high risk for common aneuploidies, a trisomy 18 or 21 will potentially be missed due to the biological phenomenon of absence of the chromosome aberration in the cytotrophoblast.

[Rapid diagnosis of the most common fetal aneuploidies with the QF-PCR method--a study of 100 cases]. / Szybka diagnostyka najczestszych aneuploidii u plodu meaoda QF-PCR--analiza 100 przypadków.

UNLABELLED: The aim of the study was to assess whether commercial kit QF-PCR can be used as the only method for rapic prenatal dia gnosis of chromosomes 13, 18, 21, X and Y aneuploidies, omitting cell culture and complete cyt6genetik analysis of fetal chromosomes. MATERIAL AND METHODS: DNA from amniocytes (94 cases) and trophoblast cells (6 cases) was analyzed witt QF-PCR according to the manufacturer's protocol. The obtained products were separated using ABI 310 Genetic Analyzer and the resulting data were analyzed using GeneMarker software. RESULTS: The results of QF-PCR were obtained in 95 out of 100 cases (95%). Abnormalities were found in 28 casea (29.5%). All these results were confirmed in subsequent cytogenetic analysis. Normal results were obtained in 62 patients (70.5%). However in that group, we found three chromosomal aberrations other than those analyzed b3 QF-PCR. Additionally two abnormal and three normal karyotypes were found in patients with inconclusive QF-POF results. CONCLUSIONS: QF-PCR is a fast and reliable tool for chromosomal aneuploidy analysis and can be used as the only method without a full analysis of the karyotype, but only in cases of suspected fetal 13, 18, 21 trisomy or numerica aberrations of X chromosome. In other cases, fetal karyotype analysis from cells obtained after cell culture should be offered to the patient.

Clinical Manifestations and Risk Factors for Complications of Philadelphia Chromosome-Negative Myeloproliferative Neoplasms.

BACKGROUND: Myeloproliferative neoplasms (MPNs) are clonal hematopoietic stem cell disorders characterized by proliferation of one or more myeloid lineages. Polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF) are classical Philadelphia chromosome (Ph)-negative MPN that have a Janus Kinase 2 (JAK2) mutation, especially JAK2V617F in the majority of patients. The major complications of Ph-negative MPNs are thrombosis, hemorrhage, and leukemic transformation. OBJECTIVE: To study clinical manifestations including symptoms, signs, laboratory findings, and JAK2V617F mutations of Ph-negative MPN (PV, ET and PMF) as well as their complications. MATERIALS AND METHODS: All Ph-negative MPN (PV, ET and PMF) patients who attended the Hematology Clinic at Maharaj Nakorn Chiang Mai Hospital from January, 1 2003 through December, 31 2013 were retrospectively reviewed for demographic data, clinical characteristics, complete blood count, JAK2V617F mutation analysis, treatment, and complications. RESULTS: One hundred and fifty seven patients were included in the study. They were classified as PV, ET and PMF for 68, 83 and 6 with median ages of 60, 61, and 68 years, respectively. JAK2V617F mutations were detected in 88%, 69%, and 100% of PV, ET and PMF patients. PV had the highest incidence of thrombosis (PV 29%, ET 14%, and PMF 0%) that occurred in both arterial and venous sites whereas PMF had the highest incidence of bleeding (PMF 17%, ET 11%, and PV 7%). During follow up, there was one ET patient that transformed to acute leukemia and five cases that developed thrombosis (three ET and two PV patients). No secondary myelofibrosis and death cases were encountered. CONCLUSIONS: Ph-negative MPNs have various clinical manifestations. JAK2V617F mutations are present in the majority of PV, ET, and PMF patients. This study confirmed that thrombosis and bleeding are the most significant complications in patients with Ph-negative MPN.

[Chromosomal aberrations--the cause of spontaneous abortions]. / Aberracje chromosomowe jako przyczyna poronien samoistnych.

UNLABELLED: The genetic factor remains the most frequent cause of spontaneous abortions. Examination of the fetal tissue from spontaneous miscarriages shows that 75% of them were caused by abnormal karyotype. Other reasons, albeit rare, included submicroscopic genomic rearrangements, monogenic diseases, and polygenic inheritance disorders of the embryo. OBJECTIVE: The aim of the study was to analyze the incidence of chromosomal aberrations in material from the miscarriage. MATERIAL AND METHODS: The study included 47 samples of miscarriage material from 47 women. Fluorescent hybridization in-situ (FISH) was used for genetic examination. RESULTS: Chromosomal abnormalities were diagnosed in 72% of the samples, with trisomy 21 (25.5%), trisomy 16 (17%), and trisomy 18 (12.8%) as the most common. An abnormal number of copies of chromosome 18, 21, 22, indicating the coexistence of trisomy 18, 21, 22, was detected in 1 patient. It was another miscarriage in case of 14 subjects (29.8%). CONCLUSIONS: Chromosomal aberrations were diagnosed in the majority of fetal tissue samples from spontaneous miscarriages. More than one chromosomal aberration in a single embryo is an extremely rare occurrence. Miscarriage due to chromosomal aberrations occurred in the vast majority of women > 35 years of age.

Reconstitution of human rRNA gene transcription in mouse cells by a complete SL1 complex.

An important characteristic of the transcription of a ribosomal RNA gene (rDNA) mediated by DNA-dependent RNA polymerase (Pol) I is its stringent species specificity. SL1/TIF-IB is a key complex for species specificity, but its functional complex has not been reconstituted. Here, we established a novel and highly sensitive monitoring system for Pol I transcription to reconstitute the SL1 activity in which a transcript harboring a reporter gene synthesized by Pol I is amplified and converted into translatable mRNA by the influenza virus RNA-dependent RNA polymerase. Using this monitoring system, we reconstituted Pol I transcription from the human rDNA promoter in mouse cells by expressing four human TATA-binding protein (TBP)-associated factors (TAFIs) in the SL1 complex. The reconstituted SL1 also re-activated human rDNA transcription in mouse A9 cells carrying an inactive human chromosome 21 that contains the rDNA cluster. Chimeric SL1 complexes containing human and mouse TAFIs could be formed, but these complexes were inactive for human rDNA transcription. We conclude that four human TAFIs are necessary and sufficient to overcome the barrier of species specificity for human rDNA transcription in mouse cells.

[CYTYOGENETIC MARKERS OF BRONCHIAL ASTHMA IN CHILDREN].

The learning of cytyogenetic special of cariotip in children with the bronchial asthma maked by course of the investigation of prometahyases chromosomes of limphocytes of the periferic bloods. The quantity of association of acrocentric chromosome was analised. The 82 children in age 6-18 years old with the bronchial asthma and with the different control were learned by results of asthma--test control. In children with the noncontrol bronchial asthma the big frequency of of association of acrocentric chromosome 13-15 (D-D), 21-22 (G-G) n 13-15--21-22 (D-G) were received. In patients with the bronchial asthma the lover mitotic activity by healthy were marked (P(N) < 0.05). With the degree of activity it was decreased.

Neutrality of miniSTR D22S1045 marker by Ewing's sarcoma phenotype.

Neutrality investigations of markers with forensic use are important to see if a phenotypic trait is being expressed in relation to the alleles of the marker. MiniSTR marker D22S1045 (locus 22q12.3) is localized near the breakpoint region of the EWS gene (22q12.2), which leads to the development of Ewing's Sarcoma. Analyzing allele frequencies and linkage disequilibrium in Ewing's sarcoma patients and non-affected populations, we found that the marker mD22S1045 was neutral when related to Ewing's Sarcoma.

Familial focal epilepsy with variable foci mapped to chromosome 22q12: expansion of the phenotypic spectrum.

We aimed to refine the phenotypic spectrum and map the causative gene in two families with familial focal epilepsy with variable foci (FFEVF). A new five-generation Australian FFEVF family (A) underwent electroclinical phenotyping, and the original four-generation Australian FFEVF family (B) (Ann Neurol, 44, 1998, 890) was re-analyzed, including new affected individuals. Mapping studies examined segregation at the chromosome 22q12 FFEVF region. In family B, the original whole genome microsatellite data was reviewed. Five subjects in family A and 10 in family B had FFEVF with predominantly awake attacks and active EEG studies with a different phenotypic picture from other families. In family B, reanalysis excluded the tentative 2q locus reported. Both families mapped to chromosome 22q12. Our results confirm chromosome 22q12 as the solitary locus for FFEVF. Both families show a subtly different phenotype to other published families extending the clinical spectrum of FFEVF.

Distinguishing the co-ancestries of haplogroup G Y-chromosomes in the populations of Europe and the Caucasus.

Haplogroup G, together with J2 clades, has been associated with the spread of agriculture, especially in the European context. However, interpretations based on simple haplogroup frequency clines do not recognize underlying patterns of genetic diversification. Although progress has been recently made in resolving the haplogroup G phylogeny, a comprehensive survey of the geographic distribution patterns of the significant sub-clades of this haplogroup has not been conducted yet. Here we present the haplogroup frequency distribution and STR variation of 16 informative G sub-clades by evaluating 1472 haplogroup G chromosomes belonging to 98 populations ranging from Europe to Pakistan. Although no basal G-M201* chromosomes were detected in our data set, the homeland of this haplogroup has been estimated to be somewhere nearby eastern Anatolia, Armenia or western Iran, the only areas characterized by the co-presence of deep basal branches as well as the occurrence of high sub-haplogroup diversity. The P303 SNP defines the most frequent and widespread G sub-haplogroup. However, its sub-clades have more localized distribution with the U1-defined branch largely restricted to Near/Middle Eastern and the Caucasus, whereas L497 lineages essentially occur in Europe where they likely originated. In contrast, the only U1 representative in Europe is the G-M527 lineage whose distribution pattern is consistent with regions of Greek colonization. No clinal patterns were detected suggesting that the distributions are rather indicative of isolation by distance and demographic complexities.

Absence of SYCP3 mutations in women with recurrent miscarriage with at least one trisomic miscarriage.

Mutations within the coding regions of the synaptonemal complex gene SYCP3 have previously been reported in women with recurrent miscarriage. The present study found no mutations in any of the coding exons or the intron/exon boundaries among 50 recurrent miscarriage patients with at least one documented trisomic miscarriage, suggesting that mutations in SYCP3 do not contribute significantly to risk for recurrent miscarriage through maternal meiotic nondisjunction.

Development of patient-specific neurons in schizophrenia using induced pluripotent stem cells.

Induced pluripotent stem cell (iPSC) technology has the potential to transform regenerative medicine. It also offers a powerful tool for establishing in vitro models of disease, in particular, for neuropsychiatric disorders where live human neurons are essentially impossible to procure. Using iPSCs derived from three schizophrenia (SZ) patients, one of whom has 22q11.2del (velocardiofacial syndrome; VCFS), the authors developed a culture system to study SZ on a molecular and cellular level. SZ iPSCs were differentiated into functional, primarily glutamatergic neurons that were able to fire action potentials after ∼8 weeks in culture. Early differentiating neurons expressed a number of transcription factors/chromatin remodeling proteins and synaptic proteins relevant to SZ pathogenesis, including ZNF804A, RELN, CNTNAP2, CTNNA2, SMARCA2, and NRXN1. Although a small number of lines were developed in this preliminary study, the SZ line containing 22q11.2del showed a significant delay in the reduction of endogenous OCT4 and NANOG expression that normally occurs during differentiation. Constitutive expression of OCT4 has been observed in Dgcr8-deficient mouse embryonic stem cells (mESCs); DGCR8 maps to the 22q11.2-deleted region. These findings demonstrate that the method of inducing neural differentiation employed is useful for disease modeling in SZ and that the transition of iPSCs with 22q11.2 deletions towards a differentiated state may be marked by subtle changes in expression of pluripotency-associated genes.

[Do chromosomal abnormalities reappear in subsequent pregnancies and how often?]. / Czy i jak czesto aberracje chromosomowe zarodków powtarzaja sie w kolejnej ciazy?

OBJECTIVE: Genetic factors are the most common causes of spontaneous abortions. 50% to 80% of first-trimester abortions reveal-chromosome abnormalities. Evidence for the recurrence of the same or another chromosome abnormality in the next pregnancy is scarce. THE AIM: The aim of our study was to estimate recurrence risk of abortus aneuploidy and to find out whether karyotyping of the abortus allows the prognose subsequent pregnancy outcomes. MATERIAL AND METHODS: Paraffin-embedded chorions have undergone cytogenetic examination using FISH with chromosome-specific probes. 57 chorions from 26 women have been assessed, including chorions from two consecutive abortions from 18 women and chorions from three consecutive abortions from 5 women. RESULTS: 38.6% of 57 specimens had chromosome aberrations. The most prevalent anomalies were 16, 21 and 18 trisomies. 23 patients had a subsequent abortion karyotyped; 15 had a normal initial karyotype and 8 had an aberrant initial karyotype. 3 out of the 8 patients had a repeated chromosome anomaly 5 out of the 15 patients who initially miscarried an aneuploid embryo, had a subsequent miscarriage of an aneuploid embryo. Only 3 (13.04%) out of the 23 patients displayed aneuploidy in each abortus. CONCLUSION: (1) Chromosome aberrations can reappear in subsequent pregnancies in the same patient and may be the cause of recurrent miscarriages. (2) The value of embryo/fetal karyotyping is not decisive in prognosis of subsequent pregnancy outcome. (3) Abnormal fetal karyotype can occur regardless of other causes of pregnancy loss.

Genetic alterations in children and adolescents with acute myeloid leukaemia.

Acute Myeloid Leukemia is a clinically and genetically heterogeneous disease, in which cytogenetic aberrations are the most important factors to determine biological behavior and prognosis. More than 20 different chromosomal abnormalities have been identified in a high percentage of children (70-85%) with the novo AML. We reviewed the most frequently found and the impact of these aberrations on prognosis. Differences according to the age of patients and mainly in relation to adult population have been enhanced, although the low incidence of AML in children and the high number of abnormalities make difficult to accurately define the prognosis significance of these aberrations.

Genetic alterations in children and adolescents with acute myeloid leukaemia

Acute Myeloid Leukemia is a clinically and genetically heterogeneous disease, in which cytogenetic aberrations are the most important factors to determine biological behavior and prognosis. More than 20 different chromosomal abnormalities have been identified in a high percentage of children (70-85%) with the novo AML. We reviewed the most frequently found and the impact of these aberrations on prognosis. Differences according to the age of patients and mainly in relation to adult population have been enhanced, although the low incidence of AML in children and the high number of abnormalities make difficult to accurately define the prognosis significance of these aberrations (AU)

Metabolism and karyotype analysis of oocytes from patients with polycystic ovary syndrome.

BACKGROUND: Polycystic ovary syndrome (PCOS) is associated with metabolic disturbances which include impaired insulin signalling and glucose metabolism in ovarian follicles. The oocyte is metabolically dependent upon its follicle environment during development, but it is unclear whether PCOS or polycystic ovarian (PCO) morphology alone affect oocyte metabolism and energy-demanding processes such as meiosis. METHODS: Immature human oocytes were donated by PCOS (n = 14), PCO (n = 14) and control (n = 46) patients attending the assisted conception programme at Leeds Teaching Hospitals NHS Trust. Oocytes were cultured individually and carbohydrate metabolism was assessed during overnight in vitro maturation (IVM). Meiotic status was assessed and oocyte intracellular nicotinamide adenine dinucleotide phosphate (NAD(P)H) content and mitochondria activity were measured prior to karyotype analysis by multifluor in situ hybridization. RESULTS: Patient aetiology had no significant effect on oocyte maturation potential or incidence of numerical chromosome abnormalities (44%), although PCOS and PCO oocytes were more likely to suffer predivision. Group G chromosomes were most likely to be involved in non-disjunction and predivision. PCOS was associated with increased glucose consumption (2.06 +/- 0.43 and 0.54 +/- 0.12 pmol/h for PCOS and control oocytes, respectively) and increased pyruvate consumption (18.4 +/- 1.2 and 13.9 +/- 0.9 pmol/h for PCOS and control oocytes, respectively) during IVM. Prior prescription of metformin significantly attenuated pyruvate consumption by maturing oocytes (8.5 +/- 1.8 pmol/h) from PCOS patients. Oocytes from PCO patients had intermediate metabolism profiles. Higher pyruvate turnover was associated with abnormal oocyte karyotypes (13.4 +/- 1.9 and 19.9 +/- 2.1 pmol/h for normal versus abnormal oocytes, respectively). Similarly, oocyte NAD(P)H content was 1.35-fold higher in abnormal oocytes. CONCLUSIONS: The chromosomal constitution of in vitro matured oocytes from PCOS is similar to that of controls, but aspects of oocyte metabolism are perturbed by PCOS. Elevated pyruvate consumption was associated with abnormal oocyte karyotype.

[Frequency of chromosomal aberrations in material from abortions]. / Czestosc wystepowania aberracji chromosomowych w materiale z poronien.

UNLABELLED: Examination of fetal tissue from spontaneous miscarriages shows that 50-70% of them were caused by abnormal karyotype. The most frequent genetic abnormalities include abnormal number of chromosomes, aberration of chromosomes structure and chromosome mosaic anomalies. OBJECTIVE: The aim of the study was to find out whether there is any difference in the frequency of chromosomal aberrations in patients who miscarried for the first time comparing to patients with recurrent miscarriages. MATERIAL AND METHODS: Examination was performed on 129 miscarriage material samples from 128 women. Fluorescent hybridization in-situ (FISH) was used for genetic examination. RESULTS: We received 120 results in which 45 (37,5%) were abnormal. The most frequent chromosomal aberration was trisomy followed by triploidy and monosomy of chromosome X. Among 59 samples from first miscarriage we found 25 abnormal karyotypes. In the 61 samples from the second, third and the next miscarriages we found 20 chromosomal abnormalities. CONCLUSIONS: Frequency of chromosomal aberrations in the tissue from the first miscarriage is significantly higher than in samples from second or following miscarriages, which means that genetic factors are less likely to induce recurrent miscarriages. Genetic results confirm that most chromosomal abnormalities arise de-novo.

Prenatal diagnosis of craniomaxillofacial malformations: a characterization of phenotypes in trisomies 13, 18, and 21 by ultrasound and pathology.

OBJECTIVE: To determine the relationship between trisomies 13, 18, and 21 and craniofacial malformations detected by prenatal sonography. DESIGN: During a 29-year period (1976 through 2004), prenatal sonographic findings of 69 fetuses with trisomy 13; 171 fetuses with trisomy 18; 302 fetuses with trisomy 21; and 17 fetuses with other trisomies were evaluated retrospectively, after fetal karyotype identification. Sonographic findings were compared with autopsy results in 209 patients (trisomy 13, n=39; trisomy 18, n=64; and trisomy 21, n=106). RESULTS: For trisomy 13, cleft deformities were detected prenatally in 65.2%, and of the 39 cases with pathological information, 76.9% were found to have a cleft deformity. Ocular and orbital abnormalities were found in 28%. Malformations of the jaws and abnormal profiles were more frequently diagnosed postnatally than prenatally. For trisomy 18, abnormal profiles (41.5%) and ear abnormalities (5.3%) were the most noticeable ultrasound markers, next to abnormalities of the neurocranium (36.8%) and cranial bone configuration (21.6%). Dysmorphisms of the eye, ear, or nose were detected more frequently in autopsy cases. For trisomy 21, ultrasound showed an aberrant shape of the skull in 14.2% of fetuses. In general, the ocular-orbital and nasal abnormalities in fetuses with trisomy 18 or 21 were more evident in pathological examination than in prenatal ultrasound imaging. CONCLUSIONS: Facial anomalies are common in the major trisomies, and their prenatal sonographic identification should be improved. The above-mentioned facial anomalies provide sufficient reason to consider performing cytogenic evaluation.

[Double aortic arch: prenatal case report]. / Podwójny luk aorty: opis przypadku.

We have presented a case of prenatal double aortic arch, diagnosed by ultrasound, to demonstrate the importance of 3-vessel view by detecting aortic arch abnormalities. Double aortic arch is one the most common types of the vascular ring. The suspicion of a double aortic arch is raised by detecting the U-sign which is formed by the combination of both aortic arches and the left ductus arteriosus. In the 3-vessel view the ascending aorta and aortic arch are pointing to the right, whereas the left arch points to the left, and the trachea is seen between. The 4-chamber view appears normal, but the descending aorta is deviated medially. Literature review revealed an association between double aortic arch and congenital heart diseases in approximately 20% of cases; most often tetralogy of Fallot, transposition of great vessels, ventricular septal defects. Rarely there can be atresia of the segment of the aortic arch, which can be difficult to differentiate from other aortic arch anomalies associated with chromosomal abnormalities such as microdeletion of chromosome 22q11.