Comparative Genomic Hybridization to Microarrays in Fetuses with High-Risk Prenatal Indications: Polish Experience with 7400 Pregnancies.

The aim of this study was to determine the suitability of the comparative genomic hybridization to microarray (aCGH) technique for prenatal diagnosis, but also to assess the frequency of chromosomal aberrations that may lead to fetal malformations but are not included in the diagnostic report. We present the results of the aCGH in a cohort of 7400 prenatal cases, indicated for invasive testing due to ultrasound abnormalities, high-risk for serum screening, thickened nuchal translucency, family history of genetic abnormalities or congenital abnormalities, and advanced maternal age (AMA). The overall chromosomal aberration detection rate was 27.2% (2010/7400), including 71.2% (1431/2010) of numerical aberrations and 28.8% (579/2010) of structural aberrations. Additionally, the detection rate of clinically significant copy number variants (CNVs) was 6.8% (505/7400) and 0.7% (57/7400) for variants of unknown clinical significance. The detection rate of clinically significant submicroscopic CNVs was 7.9% (334/4204) for fetuses with structural anomalies, 5.4% (18/336) in AMA, 3.1% (22/713) in the group of abnormal serum screening and 6.1% (131/2147) in other indications. Using the aCGH method, it was possible to assess the frequency of pathogenic chromosomal aberrations, of likely pathogenic and of uncertain clinical significance, in the groups of cases with different indications for an invasive test.

Wide Fontanels, Delayed Speech Development and Hoarse Voice as Useful Signs in the Diagnosis of KBG Syndrome: A Clinical Description of 23 Cases with Pathogenic Variants Involving the ANKRD11 Gene or Submicroscopic Chromosomal Rearrangements of 16q24.3.

KBG syndrome is a neurodevelopmental autosomal dominant disorder characterized by short stature, macrodontia, developmental delay, behavioral problems, speech delay and delayed closing of fontanels. Most patients with KBG syndrome are found to have a mutation in the ANKRD11 gene or a chromosomal rearrangement involving this gene. We hereby present clinical evaluations of 23 patients aged 4 months to 26 years manifesting clinical features of KBG syndrome. Mutation analysis in the patients was performed using panel or exome sequencing and array CGH. Besides possessing dysmorphic features typical of the KBG syndrome, nearly all patients had psychomotor hyperactivity (86%), 81% had delayed speech, 61% had poor weight gain, 56% had delayed closure of fontanel and 56% had a hoarse voice. Macrodontia and a height range of -1 SDs to -2 SDs were noted in about half of the patients; only two patients presented with short stature below -3 SDs. The fact that wide, delayed closing fontanels were observed in more than half of our patients with KBG syndrome confirms the role of the ANKRD11 gene in skull formation and suture fusion. This clinical feature could be key to the diagnosis of KBG syndrome, especially in young children. Hoarse voice is a previously undescribed phenotype of KBG syndrome and could further reinforce clinical diagnosis.

[Balanced chromosomal rearrangements resulting in intellectual disability. An analysis of 22 cases with application of CGH and FISH methods]. / Zrównowazone rearanzacje chromosomowe jako przyczyna niepelnosprawnosci intelektualnej. Analiza 22 przypadków z wykorzystaniem technik CGH oraz FISH.

INTRODUCTION: In approximately 6% of balanced chromosomal rearrangements carriers, intellectual disability, dysmorphic features and congenital anomalies can be found. The abnormal phenotype might be the result of genomic imbalance or aberrant expression caused by direct breakage of a dosage sensitive gene. THE AIM OF THIS STUDY: To estimate the frequency and implication of the submicroscopic chromosomal aberrations on the abnormal phenotypes present in patients with balanced chromosomal rearrangements. Also an attempt was made to define the type of genetic defect and gene identification responsible for the intellectual disability and additional clinical features. MATERIAL AND METHODS: 22 patients with intellectual disability, congenital anomalies and dysmorphic features were analysed. Molecular karyotyping was performed in all patients using FISH with region-specific BAC clones, high resolution comparative genomic hybridization (HR-CGH) or array CGH (aCGH). A targeted or whole genome microarrays were applied. RESULTS: In 5 of 22 carriers 6 microdeletions and one duplication were found (7/22, 31.8%). Only two microdeletions were mapped at the chromosomal breakpoints. Three rearrangements had more complex structure than conventional methods demonstrated. In the chromosomal breakpoints of 21 patients the 24 genes, which functions suggest the relationship between abnormal gene expression and patients' intellectual disability, were mapped. CONCLUSIONS: We showed that in a considerable group of patients with balanced chromosomal rearrangements and abnormal phenotype the cryptic aberrations, unidentified by conventional methods, are present. These results confirmed the legitimacy of detailed analysis of the chromosomal breakpoints as well as the whole genome screening with the use of new cytogenetic methods.

Unaffected patients with a homozygous absence of the SMN1 gene.

In this report, we present three families in which we identified asymptomatic carriers of a homozygous absence of the SMN1 gene. In the first family, the bialleleic deletion was found in three of four siblings: two affected brothers (SMA type 3a and 3b) and a 25-years-old asymptomatic sister. All of them have four SMN2 copies. In the second family, four of six siblings are affected (three suffer from SMA2 and one from SMA3a), each with three SMN2 copies. The clinically asymptomatic 47-year-old father has the biallelic deletion and four SMN2 copies. In the third family, the biallelic SMN1 absence was found in a girl affected with SMA1 and in her healthy 53-years-old father who had five SMN2 copies. Our findings as well as those of other authors show that an increased number of SMN2 copies in healthy carriers of the biallelic SMN1 deletion is an important SMA phenotype modifier, but probably not the only one.

Use of sensor-augmented insulin pump in patient with diabetes and cystic fibrosis: evidence for improvement in metabolic control.

Cystic fibrosis-related diabetes (CFRD) is a frequent complication of cystic fibrosis. We report the significant improvement of diabetes control and quality of life in a CFRD patient using the sensor-augmented insulin pump. The system gives the patient the highest degree of flexibility, which is required in CFRD since food intake and activity levels vary widely from day to day, depending on the rapid changes of health status.

[Characterization of marker chromosomes using molecular cytogenetic methods in patients with mental retardation and congenital malformations]. / Charakterystyka chromosomów markerowych metodami cytogenetyki molekularnej u pacjentów z cechami niepelnosprawnosci intelektualnej i wspólistnieniem wad rozwojowych.

INTRODUCTION: Until recently, great variety of marker chromosomes and difficulties with their identification have presented a problem for cytogenetic and clinical interpretation of the karyotype. At present, molecular cytogenetic methods of chromosome analysis enable precise characterization of such abnormalities providing knowledge necessary for estimation of their genetic risk. AIM: The aim of the study was molecular cytogenetic characterization of marker chromosomes recognized in three patients, an analysis of clinical features in relation to the abnormality and estimation of genetic risk of identified markers. PATIENTS AND METHODS: Karyotypes of three phenotypically abnormal patients were estimated in lymphocytes from peripheral blood by G banding analysis. Marker chromosomes were identified by fluorescence in situ hybridization (FISH), multiplex FISH, multicolor band and high resolution comparative genomic hybridization methods. RESULTS: Marker chromosomes were identified as inv dup(22)(pter->q11.2::q11.2->pter), der(8)(:p22->q11.2:), der(2l)(:pter->q21.3:) and der(19)(:p11->q13.1). All of them contained euchromatic sequences. First marker, an inverted duplication of chromosome 22q11.2 corresponding to tetrasomy of this chromosome region was recognized in a child with partial cat eye syndrome. Two further markers derived from chromosomes 8 and 21 were found in a child with mosaic karyotype and clinical features of trisomy 8p. In the third case additional chromosome material was derived from chromosome 19 and it was found in a patient with mild mental retardation and clinical features of ovary dysgenesis. Genetic risk of identified marker chromosomes except for mar(19) was estimated as high. CONCLUSIONS: Our results provide further evidence for diagnostic value of molecular cytogenetic methods. They also confirmed the general opinion of the high risk of phenotypic abnormalities in the carriers of marker chromosomes containing euchromatic sequences.

[Epilepsy in three children with Wolf-Hirschhorn syndrome]. / Padaczka u trojga dzieci z zespolem Wolfa-Hirschhorna.

OBJECTIVES: Wolf-Hirschhorn syndrome (4p detetion) belongs to the group of disorders caused by chromosomal aberrations, associated with frequent occurrence of epilepsy. To illustrate phenotype - genotype association, the study presents 3 children with this syndrome and epilepsy. MATERIALS AND METHODS: The diagnosis of Wolf-Hirschhorn syndrome was established in 2 patients during neonatal period and in the third child, the 5 month of life. In the majority of patients characteristic phenotype and associated malformations were detected, and the low birth weight and fronto-temporal diameter of the head as well. The structural neuroimaging revealed the diffuse decrease of brain volume without neurodevelopmental malformations. The earliest manifestation of epilepsy was observed in the 4 month old child with 4p. microdeletion as a status epilepticus. In remaining two children with 4p deletion, generalised tonic-clonic seizures were observed for the first time in the 7th month and 7th year, respectively. The standard EEG was performed in infants, while in the 7 year old child a-one-hour videoEEG was recorded. RESULTS: In older children diazepam and clona-zepam were effective to abort seizures, patients became seizure free on carbamazepin and phenobarbital. In the youngest child, status epilepticus being resistant to benzodiazepins, was interrupted with difficulties. Despite generalised type of seizures, EEG revealed focal changes of bioelectrical activity of the brain in two children. In the 7 month old child there were high voltage slow waves in the parieto-temporo-occipital region, while in the 7 year old child videoEEG demonstrated inter-hemispheric asymmetry and asynchrony, and the presence of epileptic grapho-elements, such as spikes and the spike-slow wave complexes as well. CONCLUSION: Epilepsy appeared in children with Wolf-Hirschhorn syndrome with deletion and microdeletion. Status epilepticus in this syndrome may be resistant to benzodiazepins.

Genetic counselling in carriers of reciprocal chromosomal translocations involving short arm of chromosome X.

A central concept in genetic counselling is the estimation of the probability of occurrence of unbalanced progeny at birth and other unfavourable outcomes of pregnancy (miscarriages, stillbirths and early death). The estimation of the occurrence probability for individual carriers of four different X-autosome translocations with breakpoints at Xp, namely t(X;5)(p22.2;q32), t(X;6)(p11.2;q21), t(X;7)(p22.2;p11.1), and t(X;22)(p22.1;p11.1), is presented. The breakpoint positions of chromosomal translocations were interpreted using GTG, RBG and FISH-wcp. Most of these translocations were detected in women with normal phenotype, karyotyped because of repeated miscarriages and/or malformed progeny. A girl with very rare pure trisomy Xp22.1-->pter and a functional Xp disomy was ascertained in one family and her clinical picture has been described in details. It has been suggested that not fully skewed X chromosome inactivation of X-autosome translocation with breakpoint positions at Xp22 (critical segment) could influence the phenotype and risk value. Therefore, the X inactivation status was additionally evaluated by analysis of replication banding patterns using RBG technique after incorporation of BrdU. In two carriers of translocations: t(X;5)(p22.2;q32) and t(X;7)(p22.2;p11.1), late replication state of der(X) was observed in 5/100 and 10/180 analysed cells, respectively. In these both cases the breakpoint positions were clustered at the critical segment Xp22.2. In two other cases, one with the breakpoint position within [t(X;22)(p22.1;p11.1)] and one outside the critical region [t(X;6)(p11.2;q21)], fully skewed inactivation was seen. Therefore, we suggest that neither the distribution of the breakpoint positions nor fully skewed inactivation influenced the phenotype of observed t(X;A) carriers. The occurrence probabilities of the unbalanced progeny were calculated according to Stene and Stengel-Rutkowski along with application of updated available empirical data. In the studied group the values of occurrence probability for unbalanced offspring at birth ranged from 2.1% to 17%. Information on the magnitude of the individual figures may be important for women carrying a reciprocal X;A translocation when deciding upon further family planning.

Subtelomeric rearrangements: results from FISH studies in 84 families with idiopathic mental retardation.

BACKGROUND: The etiology of mental retardation (MR) is unexplained in at least 50% of cases. Recently it was shown that subtle telomeric rearrangements may be a common cause of idiopathic mental retardation (IMR). MATERIAL/METHODS: We studied 84 families with IMR and unspecific clinical features suggesting chromosomal aberration, including 59 patients with moderate to severe MR and 24 with mild MR. One healthy father of three deceased, severely MR children was also included. Fluorescence in situ hybridization (FISH) using 41 subtelomeric probes (the Chromoprobe Multiprobe--T System) was performed in all patients. RESULTS: Ten (11.9%) subtle chromosome rearrangements were identified. Nine (10.7%) were subtelomeric abnormalities. Seven were familial, with six of paternal origin. All but one were products of parental balanced reciprocal translocation or inversion. Retrospective G-banding analysis showed that six of the nine rearrangements could be seen or suspected at the 450-550 band levels. Subtelomeric abnormalities were recognized in six patients with severe/moderate (including the father of children with severe MR) and in three with mild MR. CONCLUSIONS: Our results confirm previous findings on the importance of subtelomeric rearrangements in the etiology of MR. They also show the diagnostic utility of subtelomeric FISH in detecting subtle telomeric rearrangements in IMR cases. The high proportion of familial rearrangements emphasizes their importance for genetic counseling. FISH screening was more reliable and efficient in identifying subtle telomeric abnormalities than G-banding analysis. However, as many of the subtelomeric abnormalities could be detected in retrospect even at the 550 band level, high-resolution G-banding analysis should always precede subtelomere assay. This is important for a better estimation of the real frequency of cryptic subtelomeric abnormalities.