9p Duplication Research Articles

5. Further evidence of GABRA4 and TOP3B as autism susceptibility genes

Copy number variants (CNVs) are a known contributor to neurodevelopmental conditions such as autism spectrum disorder (ASD). Both array comparative genomic hybridization and Next-Generation sequencing techniques have led to increased detection of small CNVs and the identification of many candidate susceptibility genes for ASD. We report familial inheritance of two CNVs that include genes with known involvement in neurodevelopment. These CNVs are found in various combinations among four siblings with autism spectrum disorder, as well as in their phenotypically normal parents. We describe a 2.4 Mb duplication of 4p12 to 4p11 that includes GABRA4 and other GABA receptor genes, as well as a 246 kb deletion at 22q11.22 involving the TOP3B gene. The maternally inherited 4p duplication was detected in three siblings, two of whom also had the paternally inherited 22q11.22 deletion. The fourth sibling only had the 22q11.22 deletion. These CNVs have rarely been reported in the literature. Upon review, a single publication was found describing a similar 4p duplication in three generations of a family with neurodevelopmental and neuropsychiatric disorders, as well as in an unrelated patient with autism. TOP3B falls within the distal 22q11.22 deletion syndrome and has been associated with schizophrenia, neurodevelopmental disorders including epilepsy, and cardiac defects. The identification of this family contributes to the understanding of specific genetic contributors to neurodevelopmental disorders and an emerging phenotype associated with proximal 4p duplication.

Prenatal and postnatal diagnoses and phenotype of 8p23.3p22 duplication in one family

BackgroundDistal 8p duplication is rare but clinically significant. Duplication syndrome results in variable phenotypes, such as developmental delay, intellectual disability, and malformation of the heart. We aimed to provide a better understanding of the phenotypes by studying duplication and its effects in a single family.MethodsIn a family with a previously induced labor (second fetus) at 12 weeks gestation due to increased nuchal translucency (3.5 mm), copy number variation sequencing (CNV-seq) revealed a 16.22 Mb deletion of 8p23.3p22. For their subsequent pregnancy, the family requested a prenatal diagnosis as well as CNV-seq, karyotyping and FISH testing of all family members.ResultsThe first and third children were found to have a 16.22 Mb duplication of 8p23.3p22, containing the 8p23.1 duplication syndrome region. The duplication was inherited from their father, a carrier with a translocation of 8p22 and 22q13. We confirmed that the duplication site was located on chromosome 22q13 by combining the results of CNV-seq, karyotype and FISH. The first child is a 7.5-year-old boy. At one month old, he was diagnosed with a ventricular septal defect and treated surgically at age four. His growth and intelligence developed well, and he performed well in school. His primary issue is an inability to distinguish between the blade alveolars and retroflexes in speech. The third fetus had a normal ultrasound index from beginning until birth. The family elected to continue the pregnancy, and the baby was born healthy, providing us the opportunity to evaluate the effects of 8p23.3p22 duplication by comparison with the brother.ConclusionOur study makes a significant contribution to the literature because this relatively rare condition can have significant phenotypical consequences, and an understanding of the inheritance and variability of phenotypes caused by this mutation is essential to an increased understanding of the condition.

A Beckwith-Wiedemann syndrome case with de novo 24\xa0Mb duplication of chromosome 11p15.5p14.3

BackgroundMolecular genetic testing for the 11p15-associated imprinting disorder Beckwith-Wiedemann syndrome (BWS) is challenging because of the molecular heterogeneity and complexity of the affected imprinted regions. An integrated molecular approach to analyze the epigenetic-genetic alterations is required for accurate diagnosis of BWS.Case presentation: We reported a Chinese case with BWS detected by SNP array analysis and methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA). The genetic analysis showed a de novo duplication of 24 Mb at 11p15.5p14.3 is much longer than ever reported. MS-MLPA showed copy number changes with a peak height ratio value of 1.5 (three copies) at 11p15. The duplication of paternal origin with increase of methylation index of 0.68 at H19 and decreased methylation index of 0.37 at KCNQ1OT1.ConclusionCombined chromosome microarray analysis and methylation profiling provided reliable diagnosis for this paternally derived duplication of BWS. The phenotype associated with 11p15 duplications depends on the size, genetic content, parental inheritance and imprinting status. Identification of these rare duplications is crucial for genetic counselling.

Generation of induced pluripotent stem cell GZHMCi005-A from amniotic fluid-derived cells with duplication of chromosome 8p.

Cases in which the duplication of chromosome 8p (dup 8p) is observed are characterized by facial dysmorphism, agenesis/hypoplasia of the corpus callosum, heart defects and severe mental retardation. The frequency of dup 8p cases is higher compared to other chromosomes because of the Non-allelic homologous recombination (NAHR) between two segmental duplication regions (SDs) containing olfactory receptor gene clusters, REPD (repeat-distal) and REPP (repeat-proximal), located in chromosome 8p23.1. Here we generated a human iPSC line from a patient's amniotic fluid cells with a 18Mb duplication in 8p23.3p22, which will serve as useful tools for studying dup 8p syndrome.

265 Hemivertebra: systematic review of cases with cytogenetic abnormalities, associated anomalies and proposed prenatal management

To identify cases of hemivertebra with abnormal cytogenetic studies and assess for other associated anomalies in order to provide more accurate patient counseling and prenatal management. This systematic review was conducted using PubMed (including Cochrane database) and Ovid Medline from inception through November 2019. Studies were deemed eligible for inclusion if hemivertebra with abnormal cytogenetic studies was identified in the fetal, neonatal, or infant period. Studies that described other vertebral anomalies were excluded. We identified 17 cases of hemivertebra with cytogenetic abnormalities among a total of 324 cases (5%) in our review. These include partial tetrasomy 4q, mosaic trisomy 4, mosaic trisomy 7, mosaic trisomy 9, mosaic trisomy 18q, mosaic trisomy 18; trisomy 7, trisomy 15q with monosomy 6q, partial trisomy 22; duplication of 2p; 4p- deletion, 17p deletion, 18p deletion, 18q22.2 deletion, 22q13.3 deletion; ring chromosome 21, and Fanconi’s anemia. 29% (5/17) were diagnosed prenatally, 47% (8/17) at birth, and 18% (3/17) postnatally. All cases had prenatally or postnatally diagnosed associated anomalies. 29% (5/17) had associated anomalies identified prenatally, including ear anomalies, CNS abnormalities, micrognathia, congenital heart defects, renal anomalies, clubfeet, and fetal growth restriction. Postnatally diagnosed anomalies commonly included: CNS (41%, 7/17), cardiac (53%, 9/17), skeletal (71%, 12/17) and genitourinary (59%,10/17). Hemivertebra with abnormal cytogenetic testing was always associated with malformations from other organ systems that could be missed by prenatal ultrasound alone. Those include CNS, cardiovascular, musculoskeletal, and genitourinary anomalies. Fetal echocardiogram is recommended due to the considerable association with congenital heart defects. Fetal neurosonography or MRI should be considered. Of those receiving genetic testing, karyotype or SNP microarray should be considered due to the common presence of mosaicism.

Recombinant Chromosome 7 Driven by Maternal Chromosome 7 Pericentric Inversion in a Girl with Features of Silver-Russell Syndrome

Maternal uniparental disomy of chromosome 7 is present in 5–10% of patients with Silver-Russell syndrome (SRS), and duplication of 7p including GRB10 (Growth Factor Receptor-Bound Protein 10), an imprinted gene that affects pre-and postnatal growth retardation, has been associated with the SRS phenotype. Here, we report on a 17 year old girl referred to array-CGH analysis for short stature, psychomotor delay, and relative macrocephaly. Array-CGH analysis showed two copy number variants (CNVs): a ~12.7 Mb gain in 7p13-p11.2, involving GRB10 and an ~9 Mb loss in 7q11.21-q11.23. FISH experiments performed on the proband’s mother showed a chromosome 7 pericentric inversion that might have mediated the complex rearrangement harbored by the daughter. Indeed, we found that segmental duplications, of which chromosome 7 is highly enriched, mapped at the breakpoints of both the mother’s inversion and the daughter’s CNVs. We postulate that pairing of highly homologous sequences might have perturbed the correct meiotic chromosome segregation, leading to unbalanced outcomes and acting as the putative meiotic mechanism that was causative of the proband’s rearrangement. Comparison of the girl’s phenotype to those of patients with similar CNVs supports the presence of 7p in a locus associated with features of SRS syndrome.

Lessons learned from a child with a chromosomal abnormality but no major congenital anomalies.

A 9-year-old female was referred to Genetics with the possible dual diagnoses of 3p deletion and 9p duplication syndromes based on a chromosomal microarray (CMA) report of an unbalanced chromosomal translocation resulting in 3p deletion and 9p duplication. She was the first child born to non-consanguineous German parents with an unremarkable family history. Her mother had well-controlled type 1 diabetes throughout pregnancy. Our patient was delivered at 38 weeks via caesarean section with a birth weight of 3.28 kg. The perinatal course was otherwise unremarkable. By 7 years of life, she had a history of poor growth due to feeding difficulties. The CMA was requested by her paediatrician as part of initial blood tests to investigate her poor growth. All other tests were normal. She underwent adenoidectomy after which her growth parameters improved. Her CMA showed a 4 Mb terminal loss of 3p26.3–p26.1 which included the four OMIM morbid genes (CHL1, CNTN6, CNTN4, and CRBN) implicated in the characteristic features of 3p deletion. In addition, there was a 4.4 Mb 9p24.1–p24.3 duplication, previously reported in individuals with autism and cognitive delays.

Pure 9p duplication syndrome with aplasia of the middle phalanges of the fifth fingers

9p duplication syndrome is a common congenital anomaly syndrome with specific facial features, mental and developmental retardations, and characteristic fingers. Pure 9p duplication without other chromosomal structural variations is very rare. It has recently been reported that cases with partial 9p duplication including SMARCA2 have phenotypes overlapping with Coffin–Siris syndrome (CSS). Herein, we present a family with pure 9p duplication syndrome in which phenotypes partially characteristic of CSS were identified. In one of two siblings, X-ray examination revealed hypoplasia of the distal phalanges of the fifth fingers, aplasia of the middle phalanges of the fifth fingers, and aplasia of the distal phalanges of the second to fifth toes. In pure 9p duplication together with our one affected case, 9 out of 14 cases (64.3%), excluding cases whose clinical data were unavailable, presented the absence or hypoplasia of the middle phalanges of fingers or toes. Interestingly, there are no reports on CSS with aplasia or hypoplasia of the middle phalanx. Therefore, this family might suggest that the aplasia or hypoplasia of the middle phalanges of the fifth fingers or toes is a distinct finding that can distinguish between pure 9p duplication and CSS.

Distal 3p Duplication and 22q13.3 Deletion with Severe Hypotonia Originating from a Paternal Balanced Translocation (3;22)

In this study, we present a case with distal 3p duplication and 22q13.3 deletion due to unbalanced meiotic segregation in her father carrying a balanced translocation. The 2-month-old girl was examined for her severe hypotonia, developmental delay, and mild dysmorphic appearance. Clinical features include broad forehead, hypertelorism, laterally extended eyebrows, long eyelashes, a depressed nasal root, bifid nasal tip, long philtrum, thin lips, posteriorly rotated ears, short neck, partial syndactyly of the right hand (fingers 3, 4) , and partial syndactyly of the right foot (toes 2, 3). After examination, the final karyotype was reported as: 46,XX,der(22)del(22)(qter)dup(3)(p22pter), and the array-CGH results showed arr[GRCh37] 3p26.3p22.1(93949_41518607)×3 and arr[GRCh37] 22q13.31q13.33(44554083_51224252)×1. The mother has a 46,XX karyotype, and her father carries a balanced translocation, 46,XY,t(3;22)(p26.3;q13.3). This is the first case with a distal 3p duplication and 22q13.3 deletion with severe hypotonia and developmental delay.

4q27 deletion and 7q36.1 microduplication in a patient with multiple malformations and hearing loss: a case report

BackgroundChromosome deletions of the long arm of chromosome 4 in 4q syndrome are characterized by mild facial and digital dysmorphism, developmental delay, growth retardation, and skeletal and cardiac anomalies, which is regarded as an autism spectrum disorder. Moreover, some scarce reports indicate that patients with 4q interstitial deletion and 7p duplication may present symptoms associated with hearing loss.Case presentationA boy with a severe developmental delay not only post-natal but also intrauterine and several dysmorphic features including microcephaly, ocular hypertelorism, exophthalmos, low-set ears, single palmar flexion crease, and overlapping toes presented discontinued cyanosis and recurrent respiratory infections. MRI, BAEP, echocardiogram and bronchoscopy revealed that he had persistent falcine sinus with a thin corpus callosum, left auditory pathway disorder, patent foramen ovale (2 mm), and tracheobronchomalacia with the right superior bronchus arising from the lateral posterior wall of the right main bronchus. Finally, the patient died with severe pneumonia at 10 months. Array CGH revealed a 23.62 Mb deletion at chromosome 4q27, arr [hg19] 4q27-q31.21 (121, 148, 089–144, 769, 263) × 1, and a 0.85 Mb duplication at chromosome 7q36.1, arr [hg19] 7q36.1-q36.2 (152, 510, 685–153, 363,5 98) × 3. It is rare for 4q syndrome cases or 7q duplications previously reported to have a hearing disorder, pulmonary dysplasia, and pulmonary arterial hypertension.ConclusionsThe phenotype of our patient mainly reflects the effects of haploinsufficiency of FGF2, SPATA5, NAA15, SMAD1, HHIP genes combined with a microduplication of 7q36.1.

Bir Rekombinant Kromozom 4 Olgusunun Klinik Özelliklerinin Ayrıntılı Tanımlanması

Recombinant chromosome 4 is a very rare chromosomal aberration with eleven cases reported in the literature up to date. Here we report a five years old male patient with de novo rec(4) dup(4p) del(4q). The physical examination findings were as follows: caput quadratum, flat occiput, low frontal hairline, hypertelorism, ptosis, blepharophimosis, high arched eyebrows, flat nasal root with antevert nostrils and short nose, long and smooth philtrum, thin upper lip with triangular mouth, high arched palate, dental anomalies, large low-set ears, short neck, broad chest with widely spaced nipples, micropenis, cryptorchidism. Conventional cytogenetic analysis revealed the karyotype as 46,XY,rec(4)dup(4p14p16.3)del(4q34.3q35). Flourescence in-situ hybridization (FISH) analysis with sub-telomeric probes for 4p and 4q showed duplication of 4p and deletion of 4q in recombinant chromosome 4. His parents’ chromosomal analysis and sub-telomeric FISH analysis were both normal. The patient’s final karyotype was reported as 46,XY,rec(4)dup(4p16.3p14)del(4q34.4q35).arr[hg19]4p16.3p14(68,345-36,018)x3,4q34.3q35(177,676,319-190,957,460)x1 detected by Microarray. According the literature all cases with recombinant chromosome 4 have similar clinical findings. Except for our case only one case in the literature has been reported to be de novo . In conclusion, we reported a very rare case of recombinant chromosome 4, which has the largest deletion and duplication in the literature. Further cases with similar findings would help delineation of the symptoms related to the aberration.

Breakpoint delineation in 5p- patients leads to new insights about microcephaly and the typical high-pitched cry.

BackgroundCri du chat syndrome (CdCS) is a rare syndrome caused by a partial or complete deletion of the short arm of chromosome 5 (5p‐). The main clinical features include a high‐pitched cry, facial asymmetry, microcephaly, round face at birth, epicanthal folds, hypotonia, delayed growth and development.MethodsWe studied 14 Brazilian patients with CdCS using genomic array in order to better define the 5p breakpoints and recognize copy number variations (CNVs) that contribute to clinical manifestations associated with the syndrome.ResultsArray confirmed terminal deletions in 13 patients and an interstitial deletion in one patient. It was also possible to map the breakpoints and associate a genomic region of 4.7 Mb to the development of head circumference and cat‐like cry. We also found other CNVs concomitant to the 5p deletion including a 9p duplication, a 17q deletion, and a 22q deletion in three different patients.ConclusionWith advancements of molecular cytogenomic methods in the last two decades, it was possible to evidence cryptic alterations and improve the genotype–phenotype correlation. In this work, we describe a new genomic region associated with microcephaly and cat‐like cry and highlight the importance of precise delineation of 5p deletion breakpoints and detection of other CNVs in CdCS patients to improve genotype–phenotype correlation to perform a complete clinical and molecular diagnosis.

Oligogenic Effects of 16p11.2 Copy-Number Variation on Craniofacial Development

SUMMARYA copy-number variant (CNV) of 16p11.2 encompassing 30 genes is associated with developmental and psychiatric disorders, head size, and body mass. The genetic mechanisms that underlie these associations are not understood. To determine the influence of 16p11.2 genes on development, we investigated the effects of CNV on craniofacial structure in humans and model organisms. We show that deletion and duplication of 16p11.2 have “mirror” effects on specific craniofacial features that are conserved between human and rodent models of the CNV. By testing dosage effects of individual genes on the shape of the mandible in zebrafish, we identify seven genes with significant effects individually and find evidence for others when genes were tested in combination. The craniofacial phenotypes of 16p11.2 CNVs represent a model for studying the effects of genes on development, and our results suggest that the associated facial gestalts are attributable to the combined effects of multiple genes.

A Systematic Clinical Review of Prenatally Diagnosed Tetrasomy 9p.

Tetrasomy 9p was first described in 1973 and approximately 68 cases with a variable phenotype have been reported to date with 22 of them being detected prenatally. The objective of this study was to review prenatally-reported cases of tetrasomy 9p thus far and to identify ultrasound phenotypes that may be suggestive of this specific syndrome. A PubMed database search was done in February 2018 without any restriction of publication date orjournals, with the use of the following keywords: tetrasomy 9p, tetrasomy 9p prenatal, mosaic tetrasomy 9p, mosaic tetrasomy 9p prenatal, isochromosome 9p, duplication 9p prenatal, trisomy 9p prenatal. Reported cases were included if the clinical presentation and diagnostic approach of each case was clearly described. The most common characteristics of prenatally-detected tetrasomy 9p are intrauterine growth retardation (IUGR, 57.0%), central nervous system (CNS) abnormalities (59.0%), skeletal anomalies (29.0%), genitourinary and renal anomalies (29.0%) and cardiac defects (29.0%). The phenotypic spectrum of tetrasomy 9p is rather unspecific as these findings are commonly associated with other chromosome anomalies, as well as microdeletion/microduplication or monogenic syndromes. The combination of early fetal morphology and diagnostic genetic testing enables a definite tetrasomy 9p diagnosis and effective further pregnancy management.

Report of a patient with a de novo non-recurrent duplication of 17p11.2p12 and Yq11 deletion

BackgroundThe 17p11.2p12 locus is an unstable region that is predisposed to several known genomic disorders and non-recurrent rearrangements that yield varied and wide-ranging phenotypes. Nearly 1% of male newborns have deletions in the Y chromosome; these events primarily involve the heterochromatic region, but may extend to euchromatic Yq segments containing azoospermia factor regions.Case presentationWe describe the occurrence of two independent chromosomal rearrangements that originated as de novo events in a single male patient: a 10.8-Mb duplication of 17p11.2p12 and a 14.7-Mb deletion of Yq11. This individual shares some clinical characteristics with previously described patients having one or the other of these rearrangements, including global developmental delay, short stature, hypotonia, delayed puberty, certain facial features and a generalized demyelinating sensory-motor polyneuropathy without clinical manifestation. Our patient also presents some features that were not previously described in relevant individuals, including camptodactyly, preauricular pits and hypertrichosis of the back and elbows.ConclusionsTo our knowledge, this is the first patient to be reported with independent de novo deletion/duplication events involving chromosomes 17 and Y. We discuss possible responsible mechanisms and address the phenotype, particularly in light of the clinical features that were not previously reported for patients bearing a duplication of 17p11.2p12 or a deletion of Yq11. We suggest that some of the previously reported patients with Yq11 deletion and clinical manifestations other than male infertility may have additional chromosomal imbalances that could be identified by chromosome microarray analysis, as illustrated by the present case.

Chromosome 3p Inverted Duplication with Terminal Deletion: Second Postnatal Case Report with Additional Clinical Features

Distal deletions and duplications of 3p are individually well-characterized chromosome abnormalities. Here, we report an inverted duplication of 3p with an adjacent terminal 3p deletion in a 17-month-old girl who had prenatal intrauterine growth restriction and cardiac defects. Other findings included hemangiomas, neutropenia, umbilical hernia, hypotonia, gross motor delay, microcephaly, and ptosis. Family history was noncontributory. Microarray analysis revealed a 5.37 Mb deletion of chromosome bands 3p26.1 to 3p26.3 and a 13.68 Mb duplication of 3p24.3 to 3p26.1. FISH analysis confirmed that the duplication was inverted. Upon literature review, only one postnatal patient and one second trimester pregnancy have been reported with this finding. Many of our patient's features are present in both 3p deletion and 3p duplication syndromes, including congenital heart disease, growth restriction, microcephaly, hypotonia, and developmental delay. Our patient has additional features not commonly reported in 3p deletion or duplication patients, such as aortic dilation, hemangiomas, and neutropenia. The identification of this patient contributes to additional understanding of features associated with concurrent deletion and inverted duplication in the distal 3p chromosome. This report may assist clinicians working with patients who have constellations of similar features or similar cytogenomic abnormalities.

Sensorimotor Cortical Oscillations during Movement Preparation in 16p11.2 Deletion Carriers.

Sensorimotor deficits are prevalent in many neurodevelopmental disorders like autism, including one of its common genetic etiologies, a 600 kb reciprocal deletion/duplication at 16p11.2. We have previously shown that copy number variations of 16p11.2 impact regional brain volume, white matter integrity, and early sensory responses in auditory cortex. Here, we test the hypothesis that abnormal cortical neurophysiology is present when genes in the 16p11.2 region are haploinsufficient, and in humans that this in turn may account for behavioral deficits specific to deletion carriers. We examine sensorimotor cortical network activity in males and females with 16p11.2 deletions compared with both typically developing individuals, and those with duplications of 16p11.2, using magnetoencephalographic imaging during preparation of overt speech or hand movements in tasks designed to be easy for all participants. In deletion carriers, modulation of beta oscillations (12-30 Hz) were increased during both movement types over effector-specific regions of motor cortices compared with typically developing individuals or duplication carriers, with no task-related performance differences between cohorts, even when corrected for their own cognitive and sensorimotor deficits. Reduced left hemispheric language specialization was observed in deletion carriers but not in duplication carriers. Neural activity over sensorimotor cortices in deletion carriers was linearly related to clinical measures of speech and motor impairment. These findings link insufficient copy number repeats at 16p11.2 to excessive neural activity (e.g., increased beta oscillations) in motor cortical networks for speech and hand motor control. These results have significant implications for understanding the neural basis of autism and related neurodevelopmental disorders.SIGNIFICANCE STATEMENT The recurrent ∼600 kb deletion at 16p11.2 (BP4-BP5) is one of the most common genetic etiologies of ASD and, more generally, of neurodevelopmental disorders. Here, we use high-resolution magnetoencephalographic imaging (MEG-I) to define with millisecond precision the underlying neurophysiological signature of motor impairments for individuals with 16p11.2 deletions. We identify significant increases in beta (12-30 Hz) suppression in sensorimotor cortices related to performance during speech and hand movement tasks. These findings not only provide a neurophysiological phenotype for the clinical presentation of this genetic deletion, but also guide our understanding of how genetic variation encodes for neural oscillatory dynamics.

SAT-285 Role of Chromosome Microarray in Identifying a Genetic Cause of Undervirilized External Genitalia and Growth Delay in an Infant: 6p Duplication Associated with Short Stature and Micropenis

THE CASE 4 mo M born at term 7lbs 7.5oz, 19.5 inches via C-section, referred for micropenis found during evaluation for circumcision. No history of hypoglycemia. Of note, dad is s/p hypospadias repair and is short at 5th %ile. PE showed short stature, length at 3rd %ile (-1.91 SDS), wt 53rd %ile, HC 76th %ile. Stretched penile length 1.5 cm (-2.5 SDS = 1.9cm), testes 1.5 cm each, normal. Periorbital hemangioma noted. Otherwise normal exam. Chromosome microarray showed a 6.1 Mb duplication of the terminal region of 6p, pathogenic; and a 222 kb deletion of terminal 17p (felt to have no clinical significance). Patient referred to Genetics. Parental testing showed balanced translocation in dad's chromosome 46,XY,t(6;17)(p25.1;p13.1)]. GH, TSH, FT4, LH, FSH, AMH levels normal. Total Testosterone 68 ng/dL. CAH-6 panel within expected limits. Testosterone therapy 50mg/mo x 3mos initiated to improve penile length. DISCUSSION Workup of underlying cause of male undervirilization is challenging. More often than not, a definitive diagnosis remains elusive. The current case underlines the invaluable contribution of chromosomal microarray in this endeavor. Duplication of distal fragment of chromosome 6p is extremely rare, with <50 cases reported thus far. There are several genes located in this region, and as expected, case reports thus far have a wide phenotypic variability. Common features include pre-/postnatal growth delay, developmental disability, congenital malformations of the heart, kidneys, eyes. However to our knowledge, this is the first report of a patient with 6p25pter with micropenis. Of note, a patient with 6p25pter + 22q11.2pter trisomies was reported to have penile chordee and cryptorchidism (Scarborough, et al, 1986). Patienit's dad has history of hypospadias as well, suggesting a correlation between this specific mutation and undervirilized male external genitalia. Review of 26 OMIM genes contained in the reported abnormal region showed scant known data about these genes. However, gene transcripts from 5 of these OMIM genes (DUSP22, FAM50B, HUS1B, FOXQ1, SERPINB9) were shown to be highly expressed in the testis +/- brain in humans/animals, suggesting a possible role that these genes play in male genital development. CONCLUSION A genetic cause of micropenis is often hard to establish. We report a case associated with a pathogenic duplication of the terminal region of 6p chromosome. To our knowledge, no such case has been previously reported. This rare chromosome abnormality does have other associated medical complications for which he needs to be monitored. The crucial role of chromosome microarray in picking up such abnormalities in workup of undevirilization is emphasized. More research is needed to elucidate the mechanism by which the affected genes influence male genital development.

Psychiatric disorders in children with 16p11.2 deletion and duplication

Deletion and duplication of 16p11.2 (BP4–BP5) have been associated with an increased risk of intellectual disability and psychiatric disorder. This is the first study to compare the frequency of a broad spectrum of psychiatric disorders in children with 16p11.2 deletion and duplication. We aimed to evaluate (1) the nature and prevalence of psychopathology associated with copy number variation (CNV) in children with 16p11.2 by comparing deletion and duplication carriers with family controls; (2) whether deletion and duplication carriers differ in frequency of psychopathology. 217 deletion carriers, 77 deletion family controls, 114 duplication carriers, and 32 duplication family controls participated in the study. Measures included standardized research diagnostic instruments. Deletion carriers had a higher frequency of any psychiatric disorder (OR = 8.9, p < 0.001), attention deficit hyperactivity disorder (ADHD) (OR = 4.0, p = 0.01), and autism spectrum disorder (ASD) (OR = 39.9, p = 0.01) than controls. Duplication carriers had a higher frequency of any psychiatric diagnosis (OR = 5.3, p = 0.01) and ADHD (OR = 7.0, p = 0.02) than controls. The prevalence of ASD in child carriers of deletions and duplications was similar (22% versus 26%). Comparison of the two CNV groups indicated a higher frequency of ADHD in children with the duplication than deletion (OR = 2.7, p = 0.04) as well as a higher frequency of overall psychiatric disorders (OR = 2.8, p = 0.02) and psychotic symptoms (OR = 4.7, p = 0.02). However, no differences between deletion and duplications carriers in the prevalence of ASD were found. Both deletion and duplication are associated with an increased risk of psychiatric disorder, supporting the importance of early recognition, diagnosis, and intervention in these groups.

Oligogenic Effects of 16p11.2 Copy Number Variation on Craniofacial Development

A copy number variant (CNV) of 16p11.2, which encompasses 30 genes, is associated with developmental and psychiatric disorders, head size and body mass. The genetic mechanisms that underlie these associations are not understood. To elucidate the effects of genes on development, we exploited the quantitative effects of CNV on craniofacial structure in humans and model organisms. We show that reciprocal deletion and duplication of 16p11.2 have characteristic “mirror” effects on craniofacial features that are conserved in human, rat and mouse. By testing gene dosage effects on the shape of the mandible in zebrafish, we show that the distribution of effects for all individual genes is consistent with that of the CNV, and some combinations have non-additive effects. Our results suggest that, at minimum, one third of genes within the 16p11.2 region influence craniofacial development, and the facial gestalt of each CNV represents a product of 30 dosage effects.