Congenital chromoanagenesis in the routine postnatal chromosomal microarray analyses.

Chromosomal microarray analyses (CMA) have greatly increased both the yield and diagnostic accuracy of postnatal analysis; it has been used as a first-tier cytogenetic test in patients with intellectual disability, autism spectrum disorder, and multiple congenital abnormalities. During the last 15 years, we performed CMA in approximately 8,000 patients with neurodevelopmental and/or congenital disorders, of which 13 (0.16%) genetically catastrophic complex chromosomal rearrangements were identified. These ultrarare rearrangements showed clustering of breakpoints, characteristic of chromoanagenesis events. Al1 13 complex events display underlying formation mechanisms, originating either by a synchronization of the shattering of clustered chromosome regions in which regional asynchrony of DNA replication may be one of the main causes of disruption. We provide an overview of the copy number profiling in these patients. Although several previous studies have suggested that chromoanagenesis is often a genetic disease source in postnatal diagnostic screening, due to either the challenge of clinical interpretation of these complex rearrangements or the limitation of microarray resolution relative to the small size and complexity of chromogenic induced chromosome abnormalities, bringing further attention and to study its occurrence in the clinical setting is extremely important.

Dominant-negative kinase domain mutations in FGFR1 can explain the clinical severity of Hartsfield syndrome.

Mutations in FGFR1 have recently been associated with Hartsfield syndrome, a clinically distinct syndromic form of holoprosencephaly (HPE) with ectrodactly, which frequently includes combinations of craniofacial, limb and brain abnormalities not typical for classical HPE. Unrelated clinical conditions generally without craniofacial or multi-system malformations include Kallmann syndrome and idiopathic hypogonadotropic hypogonadism. FGFR1 is a principal cause for these less severe diseases as well. Here we demonstrate that of the nine FGFR1 mutations recently detected in our screen of over 200 HPE probands by next generation sequencing, only five distinct mutations in the kinase domain behave as dominant-negative mutations in zebrafish over-expression assays. Three FGFR1 mutations seen in HPE probands behave identical to wild-type FGFR1 in rescue assays, including one apparent de novo variation. Interestingly, in one HPE family, a deleterious FGFR1 allele was transmitted from one parent and a loss-of-function allele in FGF8 from the other parent to both affected daughters. This family is one of the clearest examples to date of gene:gene synergistic interactions causing HPE in humans.

Chromothripsis with at least 12 breaks at 1p36.33-p35.3 in a boy with multiple congenital anomalies.

Terminal deletion in the short arm of chromosome 1 results in a disorder described as 1p36 deletion syndrome. The resulting phenotype varies among patients including mental retardation, developmental delay, sensorineural hearing loss, seizures, heart defects, and distinct facies. In the present case, we performed array-comparative genomic hybridization in a boy with multiple congenital malformations presenting some features overlapping the 1p36 deletion phenotype for whom chromosomal analysis did not reveal a terminal deletion in 1p. Results showed complex chromosome rearrangements involving the 1p36.33-p35.3 region. While the mechanism of origin of these rearrangements is still unclear, chromothripsis-a single catastrophic event leading to shattering chromosomes or chromosome regions and rejoining of the segments-has been described to occur in a fraction of cancers. The presence of at least 12 clustered breaks at 1p and apparent lack of mosaicism in the present case suggests that a single event like chromothripsis occurred. This finding suggests that chromothripsis is responsible for some constitutive complex chromosome rearrangements.

Microphthalmia, Linear Skin Defects, Callosal Agenesis, and Cleft Palate in a Patient with Deletion at Xp22.3p22.2.

The authors describe the clinical findings observed in a Brazilian girl that are suggestive of microphthalmia and linear skin defects (MLS) also known as MIDAS syndrome (OMIM #309801). She also presented with short stature, agenesis of corpus callosum, cleft palate, enamel defects, and genitourinary anomalies, which are rarely reported within the clinical spectrum of MLS. The 11,5 Mb deletion in Xp22.3p22.2 observed in the patient includes the entire HCCS gene (responsible for the MLS phenotype) and also encompasses several other genes involved with behavioral phenotypes, craniofacial and central nervous system development such as MID1, NLGN4X, AMELX , ARHGAP6, and TBL1X. The whole clinical features of our proband possibly represents an unusual MLS syndromic phenotype caused by an Xp22.3p22.2 continuous gene deletion.

Multisystem Involvement in a Patient with a PTCH1 Mutation: Clinical and Imaging Findings.

In this article, we report on a Brazilian female patient born to consanguineous parents and presenting with alobar holoprosencephaly, severe eye involvement, and unusual skin hyperpigmented lesions. She was found to have a mutation (c.2240T > C; p.Val751Gly) in exon 15 of the PTCH1 gene. Mutations in this gene are associated with the nevoid basal cell carcinoma syndrome (NBCCS, OMIM 109400) and, in other instances, with holoprosencephaly (holoprosencephaly-7, OMIM 610828). Severe eye involvement ranging from orbital coloboma to microphthalmia has been seldom reported in patients with NBCCS with PTCH1 mutations. To our knowledge, this is the first report of an individual with central nervous system, skin, and eye manifestations due to a PTCH1 mutation. Mechanisms involved in these multisystem manifestations are discussed.

Interstitial 1q21.1 Microdeletion Is Associated with Severe Skeletal Anomalies, Dysmorphic Face and Moderate Intellectual Disability.

We report on a Brazilian patient with a 1.7-Mb interstitial microdeletion in chromosome 1q21.1. The phenotypic characteristics include microcephaly, a peculiar facial gestalt, cleft lip/palate, and multiple skeletal anomalies represented by malformed phalanges, scoliosis, abnormal modeling of vertebral bodies, hip dislocation, abnormal acetabula, feet anomalies, and delayed neuropsychological development. Deletions reported in this region are clinically heterogeneous, ranging from subtle phenotypic manifestations to severe congenital heart defects and/or neurodevelopmental findings. A few genes within the deleted region are associated with congenital anomalies, mainly the RBM8A, DUF1220, and HYDIN2 paralogs. Our patient presents with a spectrum of unusual malformations of 1q21.1 deletion syndrome not reported up to date.

Cleft lip/palate, short stature, and developmental delay in a boy with a 5.6-mb interstitial deletion involving 10p15.3p14.

The chromosome interval 10p15.3p14 harbors about a dozen genes. This region has been implicated in a few well-known human phenotypes, namely HDR syndrome (hypoparathyroidism, sensorineural deafness, and renal dysplasia) and DGS2 (DiGeorge syndrome 2), but a number of variable phenotypes have also been reported. Cleft lip/palate seems to be a very unusual finding within the clinical spectrum of patients with this deletion. Here, we report a male child born with short stature, cleft lip/palate, and feeding problems who was found to have a 5.6-Mb deletion at 10p15.3p14.

Congenital Heart Disease Revealing Familial 22q11 Deletion Syndrome

Abstract Congenital heart defects are the most common birth defects and the leading cause of mortality in the first year of life. It is well known that the 22q11 deletion syndrome (22q11DS) is the most common microdeletion syndrome in humans and that congenial heart diseases (CHDs) are one of the most common phenotypic manifestations. However, it should be noted that the 22q11 deletion was also found in a significant number of patients with isolated CHD. The 22q11DS phenotype may include cardiovascular anomalies, palatal abnormalities, nasal voice, immune deficiency, endocrine dysfunctions, a varying degree of cognitive deficits and intellectual disabilities, velopharyngeal insufficiency, and characteristic craniofacial dysmorphism. This condition affects about 1 in 4,000 live births, making 22q11DS the most common microdeletion syndrome in humans. Here we describe the cases of three children who were referred to the clinical hospital center with the diagnosis of CHD, but with no direct signs of 22q11DS. Investigation of familial data led us to suspect that the mothers could be carriers of 22q11DS. The multiplex ligation-dependent probe amplification (MLPA) testing confirmed that the patients and mothers exhibited 3 Mb 22q11 deletions, which justified the clinical signs in the mothers and the CHD in children. In the presence of a few characteristics that are common of a spectrum of some known syndromes, a familial examination can provide clues to a definitive diagnosis, as well as to the prevention of diseases and genetic counseling of these patients.

Sonic hedgehog (SHH) mutation in patients within the spectrum of holoprosencephaly.

Holoprosencephaly (HPE) is a malformation sequence where the cerebral hemispheres fail to separate into distinct left and right halves. It can be associated with midline structural anomalies of the central nervous system and/or face. SHH is the major gene implicated in HPE and it plays a critical role in early forebrain and central nervous system development. SHH is expressed in the human embryo in the notochord, the floorplate of the neural tube, and the posterior limb buds. In the present study we performed mutational analysis of the entire coding region of the SHH gene in 37 unrelated individuals with the HPE spectrum. Three different variants were found throughout the extent of the gene. No genotype-phenotype correlation is evident based on the type or position of the mutations. This study confirms the great genetic heterogeneity of the disease and the difficulty to establish genotype-phenotype correlations.

Quality evaluation of DNA obtained from stored human saliva and its applicability to identification in Forensic Dentistry / Avaliação da qualidade do DNA extraído de saliva humana armazenada e sua aplicabilidade na identificação em Odontologia Legal

Purpose: This study evaluated the quality of DNA obtained from stored human saliva and its applicability to human identification. Methods: The saliva samples of 20 subjects, collected in the form of saliva in natura and from mouth swabs and stored at -20ºC, were analyzed. After 7 days, the DNA was extracted from the 40 saliva samples and subjected to PCR and electrophoresis. After 180 days, the technique was repeated with the 20 swab samples. Results: The first-stage results indicated that DNA was successfully extracted in 97.5% of reactions, 95% of saliva in natura and 100% of swab saliva samples, with no statistically significant difference between the forms of saliva. In the second phase, the result was positive for all 20 analyzed samples (100%). Subsequently, in order to analyze the quality of the DNA obtained from human saliva, the SIX3-2 gene was tested on the 20 mouth swab samples, and the PCR products were digested using the MbO1 restriction enzyme to evaluate polymorphisms in the ADRA-2 gene, with positive results for most samples. Conclusion: It was concluded that the quantity and quality of DNA from saliva and the techniques employed are adequate for forensic analysis of DNA.

Objetivo: Este trabalho objetivou avaliar a qualidade do DNA obtido de saliva humana armazenada e sua aplicabilidade da identificação de pessoas. Metodologia: Analisaram-se amostras salivares de n=20 sujeitos da pesquisa, coletadas nas formas de saliva in natura e de swab bucal, sendo armazenadas a 20ºC. Após 7 dias, o DNA foi extraído das 40 amostras de saliva e submetido à PCR e à eletroforese. Após 180 dias repetiu-se a técnica nas 20 amostras de swab. Resultados: Os resultados da primeira etapa indicaram que o DNA foi extraído com sucesso em 97,5% das reações, e, analisando-se separadamente, em 95% de saliva in natura e em 100% da saliva do swab, não havendo diferenças estatisticamente significantes entre as duas formas de saliva. Na segunda fase, o resultado foi positivo para as 20 amostras analisadas (100%). Posteriormente, para analisar a qualidade do DNA obtido da saliva humana, o gene SIX3-2 foi testado nas 20 amostras de swab bucal e foi feita a digestão do produto da PCR com a enzima de restrição MbO1 para avaliar polimorfismo do gene ADRA-2 obtendo-se resultados positivos para a maioria das amostras. Conclusão: Concluiu-se que a quantidade e a qualidade do DNA advindo de saliva e as técnicas empregadas estão adequadas à análise forense do DNA.