16p13.11 microduplication in 45 new patients: refined clinical significance and genotype-phenotype correlations.

BACKGROUND: The clinical significance of 16p13.11 duplications remains controversial while frequently detected in patients with developmental delay (DD), intellectual deficiency (ID) or autism spectrum disorder (ASD). Previously reported patients were not or poorly characterised. The absence of consensual recommendations leads to interpretation discrepancy and makes genetic counselling challenging. This study aims to decipher the genotype-phenotype correlations to improve genetic counselling and patients' medical care. METHODS: We retrospectively analysed data from 16 013 patients referred to 12 genetic centers for DD, ID or ASD, and who had a chromosomal microarray analysis. The referring geneticists of patients for whom a 16p13.11 duplication was detected were asked to complete a questionnaire for detailed clinical and genetic data for the patients and their parents. RESULTS: Clinical features are mainly speech delay and learning disabilities followed by ASD. A significant risk of cardiovascular disease was noted. About 90% of the patients inherited the duplication from a parent. At least one out of four parents carrying the duplication displayed a similar phenotype to the propositus. Genotype-phenotype correlations show no impact of the size of the duplicated segment on the severity of the phenotype. However, NDE1 and miR-484 seem to have an essential role in the neurocognitive phenotype. CONCLUSION: Our study shows that 16p13.11 microduplications are likely pathogenic when detected in the context of DD/ID/ASD and supports an essential role of NDE1 and miR-484 in the neurocognitive phenotype. Moreover, it suggests the need for cardiac evaluation and follow-up and a large study to evaluate the aortic disease risk.

Familial X/Y Translocation Encompassing ARSE in Two Moroccan Siblings with Sensorineural Deafness.

Unbalanced translocations involving X and Y chromosomes are rare and associated with a contiguous gene syndrome. The clinical phenotype is heterogeneous including mainly short stature, chondrodysplasia punctata, ichthyosis, hypogonadism, and intellectual disability. Here, we report 2 brothers with peculiar gestalt, short stature, and hearing loss, who harbor an X/Y translocation. Physical examination, brainstem acoustic potential evaluation, bone age, hormonal assessment, and X-ray investigations were performed. Because of their dysmorphic features, karyotyping, FISH, and aCGH were carried out. The probands had short stature, hypertelorism, midface hypoplasia, sensorineural hearing loss, normal intelligence as well as slight radial and ulnar bowing with brachytelephalangy. R-banding identified a derivative X chromosome with an abnormally expanded short arm. The mother was detected as a carrier of the same aberrant X chromosome. aCGH disclosed a 3.1-Mb distal deletion of chromosome region Xp22.33pter. This interval encompasses several genes, especially the short stature homeobox (SHOX) and arylsulfatase (ARSE) genes. The final karyotype of the probands was: 46,Y,der(X),t(X;Y)(p22;q12).ish der(X)(DXYS129-,DXYS153-)mat.arr[hg19] Xp22.33(61091_2689408)×1mat,Xp22.33(2701273_3258404)×0mat,Yq11.222q12 (21412851_59310245)×2. Herein, we describe a Moroccan family with a maternally inherited X/Y translocation and discuss the genotype-phenotype correlations according to the deleted genes.

Homozygous silencing of T-box transcription factor EOMES leads to microcephaly with polymicrogyria and corpus callosum agenesis.

Neural progenitor proliferation and migration influence brain size during neurogenesis. We report an autosomal recessive microcephaly syndrome cosegregating with a homozygous balanced translocation between chromosomes 3p and 10q, and we show that a position effect at the breakpoint on chromosome 3 silences the eomesodermin transcript (EOMES), also known as T-box-brain2 (TBR2). Together with the expression pattern of EOMES in the developing human brain, our data suggest that EOMES is involved in neuronal division and/or migration. Thus, mutations in genes encoding not only mitotic and apoptotic proteins but also transcription factors may be responsible for malformative microcephaly syndromes.

Characterization of a rare short arm heteromorphism of chromosome 22 in a girl with down-syndrome like facies.

Chromosomal heteromorphisms are described as interindividual variation of chromosomes without phenotypic consequence. Chromosomal polymorphisms detected include most regions of heterochromatin of chromosomes 1, 9, 16 and Y and the short arms of all acrocentric chromosomes. Here, we report a girl with Down-syndrome such as facies and tremendously enlarged short arm of a chromosome 22. Fluorescence in situ hybridization (FISH) with a probe specific for all acrocentric short arms revealed that the enlargement p arms of the chromosome 22 in question contained exclusively heterochromatic material derived from an acrocentric short arm. Parental studies identified a maternal origin of this heteromorphism. Cryptic trisomy 21 of the Down-syndrome critical region was excluded by a corresponding FISH-probe. Here, we report, to the best of our knowledge, largest ever seen chromosome 22 short arm, being ~×1.5 larger than the normal long arm.

Currarino Syndrome in Two Moroccan Siblings with Inherited 7q36 Deletion due to Maternal t(7;21)(q36;p11)mat: A Case Report.

Introduction: Currarino syndrome is a rare syndrome with multiple congenital anomalies including sacral agenesis, anorectal malformation, and presence of a presacral mass. Currarino syndrome is considered to be an autosomal dominant inherited disorder, with low penetrance and variable expressivity, but sporadic cases have also been reported. Mutations in MNX1 gene, mapped to 7q36, are the main causes of this syndrome. To the best of our knowledge, less than 400 cases of this syndrome have been mentioned in the literature. Currarino syndrome is often seen in children and considered to be rare in adults; it is mostly found as incidental finding and suspected to be underdiagnosed. Case Presentation: Recognizing the rarity of this syndrome, we present here two siblings with incomplete form of Currarino syndrome combined with microcephaly and intellectual disability. Banding and molecular cytogenetics were used to characterize the origin of this disorder. Banding cytogenetics together with molecular cytogenetics revealed an unbalanced translocation t(7;21)(q36.2;p11.3)mat, leading to a deletion of the 7q36 region in both affected children. Conclusion: This report highlights the importance of cytogenetics in diagnosis of rare genetic syndromes, with impact on genetic counseling of patients and their families. To the best of our knowledge, this is the first Moroccan Currarino syndrome case due to an unbalanced translocation leading to a der(7)t(7;21)(q36.2;p11.3). Also, this is the first Currarino syndrome case associated with a deletion in 7q36 to be reported in Morocco.

A maternally derived complex small supernumerary marker chromosome involving chromosomes 8 and 14: case report and review of the literature.

Introduction: The majority of small supernumerary marker chromosomes (sSMCs) are derived from one single chromosome. Complex sSMCs, on the other hand, consist of genetic material derived from more than one, normally two chromosomes. Complex sSMCs involving chromosomes 8 and 14 are rarely encountered. Case presentation: We present here a 14-month-old boy born from an unrelated couple. At birth, the baby was hypotonic and had a cleft lip and palate, as well as ocular involvement. Throughout the course of development, the baby experienced feeding difficulties, stunted growth, and delayed psychomotor development. Banding together with molecular cytogenetics revealed a balanced maternal translocation t(8;14)(p22.3;q21)mat, leading due to meiotic 3:1 segregation to a partial trisomy of chromosomes 8 and 14 in the affected boy. Discussion/Conclusion: This report highlights the importance of cytogenetics in diagnosis of rare genetic disorders, with impact on genetic counselling of patients and their families. There are three comparable cases in the literature involving both chromosomes 8 and 14, but with different breakpoints; the complex sSMC derived from chromosomes 8 and 14 in this case, characterized as der(14)t(8;14) (p22.3;q21)mat.

Genome and Epigenome Disorders and Male Infertility: Feedback from 15 Years of Clinical and Research Experience.

Infertility affects around 20% of couples of reproductive age; however, in some societies, as many as one-third of couples are unable to conceive. Different factors contribute to the decline of male fertility, such us environmental and professional exposure to endocrine disruptors, oxidative stress, and life habits with the risk of de novo epigenetics dysregulation. Since the fantastic development of new "omes and omics" technologies, the contribution of inherited or de novo genomes and epigenome disorders to male infertility have been further elucidated. Many other techniques have become available to andrology laboratories for the investigation of genome and epigenome integrity and the maturation and the competency of spermatozoa. All these new methods of assessment are highlighting the importance of genetics and epigenetics investigation for assisted reproduction pathology and for supporting professionals in counselling patients and proposing different management strategies for male infertility. This aims to improve clinical outcomes while minimizing the risk of genetics or health problems at birth.

Autosomal Dominant Intellectual Development Disorder-6 (MRD6) Without Seizures Linked to a De Novo Mutation in the grin2b Gene Revealed by Exome Sequencing: A Case Report of a Moroccan Child.

Autosomal dominant intellectual development disorder-6 (MRD6) arises from a grin2b gene mutation, inducing neurodevelopmental issues. The effects of MRD6 encompass cognitive disabilities, seizures, muscle tone decline, and autism-like traits. Its severity ranges from mild impairment to severe epilepsy. The disorder's rarity is emphasized by roughly 100 reported GRIN2B-related cases, spotlighting the gene's significance in brain development. We present the case of a three-year-old Moroccan boy who was referred to a neuropediatric department for a molecular diagnosis. Initial genetic testing yielded inconclusive results, and subsequent tests for Angelman syndrome and metabolic diseases showed no abnormalities. Given the complexity of the disorder, exome sequencing was employed to identify the underlying genetic cause. Exome sequencing identified a nonsense (STOP) mutation c.3912C>G (p.Tyr1304Ter) in the grin2b gene in the heterozygous state known to be present in MRD6 (Online Mendelian Inheritance in Man (OMIM) 613970). The family segregation study shows that this is a de novo variant, which is confirmed by Sanger sequencing. This variant has not been previously reported in the GnomAD database. Based on current scientific knowledge, the variant is considered pathogenic (PVS1, PS2, PM2, PP3, PP5) according to the criteria of the American College of Medical Genetics and Genomics (ACMG). The mutation in the grin2b gene (p.Tyr1304Ter) was predicted to be deleterious through bioinformatics analysis tools. This study highlights the crucial role of the grin2b gene in normal brain development and communication within the nervous system. It also sheds light on the impact of a novel genetic mutation, identified through exome sequencing, on causing an intellectual developmental disorder in a child patient from Morocco.

Complex translocation leading to13q interstitial deletion in a Moroccan child with retinoblastoma and intellectual disability.

BACKGROUND: Retinoblastoma (RB) is the most common malignant intraocular tumor in children; it affects their eyes often even prenatally. RB may be sporadic or familial, due to germinal mutation in RB1 gene or by abnormal chromosomal abnormalities involving RB1 gene, located in 13q14. Monosomy of subband 13q14 as a partial deletion can also be responsible for RB with additional symptoms. The latter may be RB associated with psychomotor retardation, macrocephaly, broad forehead, thick earlobes, and bulbous nose. MATERIALS AND METHODS: We present here the case of a boy from a consanguineous marriage with bilateral retinoblastoma, intellectual disability and facial dysmorphic features. Classical and molecular cytogenetics were used to recognize genotype-phenotype association. RESULTS: The karyotype showed a three way translocation involving chromosomes 5, 12 and 13. Further molecular cytogenetics analysis revealed a deletion of 13q14 involving the tumor suppressor gene RB1. CONCLUSION: This case highlights the impact of classical and molecular cytogenetics in diagnosis of rare genetic syndromes and for the genetic counselling of patients and their families. Pure molecular karyotyping analyses would miss the underlying chromosomal mechanism leading to the rearrangement.

Near tetrapoloid karyotype with translocation t(11;14) in a Moroccan patient with amyloid light-chain amyloidosis and multiple myeloma.

Cytogenetic and iFISH plays a major part in the diagnosis of the MM and have an important prognostic significance. 10-15% of patients with amyloidosis will also have multiple myeloma (MM). Few studies have addressed the clinical and cytogenetic features of patients with AL amyloidosis with concurrent multiple myeloma. This study of MM case in which we found a near tetraploid complex karyotype with the t(11;14) (q13;q32) abnormality in cytogenetic analysis and the presence of t(4;14) and del(17p) by iFISH, referred to several studies which showed the translocation t(11;14) as the most frequent abnormality in both AL amyloidosis and MM.

Insulin-like growth factor type 1 deficiency in a Moroccan patient with de novo inverted duplication 9p24p12 and developmental delay: a case report.

BACKGROUND: 9p duplication is a structural chromosome abnormality, described in more than 150 patients to date. In most cases the duplicated segment was derived from a parent being a reciprocal translocation carrier. However, about 15 cases with de novo 9p duplication have been reported previously. Clinically, this condition is characterized by mental retardation, short stature, developmental delay, facial dysmorphism, hand and toe anomalies, heart defects and/or ocular manifestations. CASE PRESENTATION: We report here the case of a 2-year-old Moroccan girl with a de novo duplication of 9p24 to p12. Clinical manifestations included failure to thrive, psychomotor delay, microcephaly, dysmorphic features, equinus feet, and umbilical hernia. Further clinical investigations showed an insulin-like growth factor type 1 deficiency. Banding cytogenetics identified a derivative chromosome 9, with an abnormally elongated short arm. Molecular cytogenetics based on multicolor banding probes characterized an inverted duplication 9p24 to p12 involving several genes especially an insulin-like growth factor binding protein named insulin-like growth factor binding protein-like 1, which seemed to be overexpressed, leading to the insulin-like growth factor deficiency in our patient. CONCLUSIONS: This study showed that insulin-like growth factor type 1 deficiency can be another feature of 9p duplication, suggesting a likely involvement of insulin-like growth factor binding protein-like 1 overexpression in growth delay. However, further studies of the gene expressions are needed to better understand the phenotype-karyotype correlations.

20p12.3 deletion is rare cause of syndromic cleft palate: case report and review of literature.

BACKGROUND: Orofacial cleft (OFC) is one of the most common congenital malformations with a global incidence of approximately 1/700 live births. Clinically, OFCs can be syndromic or non-syndromic. CASE PRESENTATION: A 5 years old boy admitted for genetic evaluation because of psychomotor delay, failure to thrive, dysmorphic features and cleft palate. Conventional cytogenetic showed a notably short p arm of one chromosome 20. FISH analysis identified the derivative chromosome 20 as a de novo 20p12.3 deletion. CONCLUSION: We present in this paper a Moroccan patient with syndromic cleft palate caused by a de novo 20p12.3 deletion, and we highlight the interest of FISH in the diagnosis confirmation of chromosomal rearrangement. In practice, 20p12.3 deletion should be considered as an etiological diagnosis in the case of syndromic cleft palate.

Cytotoxicity of elastomeric power chains in artificial saliva: an in vitro study.

INTRODUCTION: The main aim of this paper is to investigate the cytotoxicity of elastomeric power chains after stretching and immersion in a solution of artificial saliva. MATERIALS AND METHOD: Two brands of grey polyurethane power chains available from two different firms (GAC, G&H) were selected for cytotoxicity assay. Each segment was stretched up to an initial force of approximately 200 g. Then each segment was kept stretched using appropriate equipment. The samples were tested in artificial saliva at two pH levels, pH7 and pH4. Following incubation, the saliva was removed, filtered and placed in contact with cell culture media using the RD line. RESULTS AND DISCUSSION: At this supernatant dilution, no statistically significant difference was observed between the different groups of power chains studied in terms of cell viability. The GAC and G&H power chains, whether stretched or not and immerged in either pH7 or pH4 saliva, showed no toxic effect on RD cells (human cell line).

A new case of de novo 19p13.2p13.12 deletion in a girl with overgrowth and severe developmental delay.

BACKGROUND: We report clinical and molecular cytogenetic characterization of a 2 year-old girl with 19p13.2p13.12 microdeletion and compare her clinical features with those of three other patients reported before. RESULT: Array comparative genomic hybridization (aCGH) revealed in the present patient a de novo microdeletion of 1.45 Mb within 19p13.2p13.12. The deletion includes seven OMIM genes: MAN2B1, RNASEH2A, KLF1, GCDH, NFIX, CACNA1A and CC2D1A. DISCUSSION: The present case and three other patients with partially overlapping 19p13 microdeletion share the following features: psychomotor and language delay, intellectual disability, seizures, hypotonia, skeletal anomalies and facial dysmorphism. The smallest region of overlapping between all four reported patients is around 300 kb and spans only two genes: NFIX and CACNA1A. Their haploinsufficincy could be the base for the phenotype -genotype correlation.

Cytogenetic analysis of 5572 patients referred for suspected chromosomal abnormalities in Morocco.

OBJECTIVES: The aim of this study was (1) to identify the profile of patients being referred for cytogenetic analysis in Morocco, (2) to determine the prevalence and type of chromosomal abnormalities in the different groups, (3) to compare the results with those of similar studies done in other countries. MATERIAL AND METHODS: 5572 patients ranging from newborns to 50 years of age were referred to the department of medical genetics, of the Moroccan National Institute of Health between 1993 and 2010, with a variety of clinical disorders such as mental retardation; multiple congenital malformations; clinical features of Down syndrome, Turner's syndrome, and Klinefelter syndrome; ambiguous sex; sterility; amenorrhea; recurrent miscarriage; and chromosome breakage syndromes. RESULTS: Of the 5572 cases studied, 4068 (73%) had a normal karyotype and 1504 (27%) had chromosomal abnormalities. Various types of chromosomal anomalies were found. The most common autosomal abnormalities were Down syndrome (1095 cases) and Turner's syndrome (122 cases) in abnormalities of sex chromosomes. CONCLUSION: This study compares the results of cytogenetic analysis of chromosomal abnormalities in the Moroccan population with other countries and research centers. This comparison will help Moroccan clinicians to determine the priority for requesting a cytogenetic analysis in individual cases.

Tetrasomy 15q11-q13 diagnosed by FISH in a patient with autistic disorder.

We report the case of a Moroccan boy with mental retardation, hyperactivity, epilepsy, developmental problems and behavioural disorders. Cytogenetic analysis showed the presence of a supernumerary marker chromosome. Molecular cytogenetics allowed us to determine the marker as an inverted duplication of chromosome 15. It is the first case of a Moroccan patient with tetrasomy 15q in which fluorescence in situ hybridization (FISH) enabled us to specify the diagnosis. Interestingly, this patient has an infantile autism with cytogenetic abnormalities on chromosomal region 15q11-q13 as reported in patients with Autistic Disorder.