Hydatidiform Mole-Between Chromosomal Abnormality, Uniparental Disomy and Monogenic Variants: A Narrative Review.

A hydatidiform mole (HM) or molar pregnancy is the most common benign form of gestational trophoblastic disease characterized by a proliferation of the trophoblastic epithelium and villous edema. Hydatidiform moles are classified into two forms: complete and partial hydatidiform moles. These two types of HM present morphologic, histopathologic and cytogenetic differences. Usually, hydatidiform moles are a unique event, but some women present a recurrent form of complete hydatidiform moles that can be sporadic or familial. The appearance of hydatidiform moles is correlated with some genetic events (like uniparental disomy, triploidy or diandry) specific to meiosis and is the first step of embryo development. The familial forms are determined by variants in some genes, with NLRP7 and KHDC3L being the most important ones. The identification of different types of hydatidiform moles and their subsequent mechanisms is important to calculate the recurrence risk and estimate the method of progression to a malign form. This review synthesizes the heterogeneous mechanisms and their implications in genetic counseling.

A Case of Inherited t(4;10)(q26;q26.2) Chromosomal Translocation Elucidated by Multiple Chromosomal and Molecular Analyses. Case Report and Review of the Literature.

We present a complex chromosomal anomaly identified using cytogenetic and molecular methods. The child was diagnosed during the neonatal period with a multiple congenital anomalies syndrome characterized by: flattened occipital region; slight turricephaly; tall and broad forehead; hypertelorism; deep-set eyes; down slanting and short palpebral fissures; epicanthic folds; prominent nose with wide root and bulbous tip; microstomia; micro-retrognathia, large, short philtrum with prominent reliefs; low set, prominent ears; and congenital heart disease. The GTG banding karyotype showed a 46,XY,der(10)(10pter→10q26.2::4q26→4qter) chromosomal formula and his mother presented an apparently balanced reciprocal translocation: 46,XX,t(4;10)(q26;q26.2). The chromosomal anomalies of the child were confirmed by MLPA, and supplementary investigation discovered a quadruplication of the 4q35.2 region. The mother has a triplication of the same chromosomal fragment (4q35.2). Using array-CGH, we described the anomalies completely. Thus, the boy has a 71,057 kb triplication of the 4q26-q35.2 region, a 562 kb microdeletion in the 10q26.3 region, and a 795 kb quadruplication of the 4q35.2 region, while the mother presents a 795 kb triplication of the 4q35.2 region. Analyzing these data, we consider that the boy's phenotype is influenced only by the 4q partial trisomy. We compare our case with similar cases, and we review the literature data.

Wolf-Hirschhorn Syndrome: Clinical and Genetic Study of 7 New Cases, and Mini Review.

Wolf-Hirschhorn syndrome (WHS), a rare disorder determined by distal 4p deletion, is characterized by a pre and postnatal growth retardation, hypotonia, intellectual disability, epilepsy, craniofacial dysmorphism, and congenital fusion anomalies. The clinical aspects are dependent on the deletion' size. Our aim was to identify rare specific characteristics in a cohort of seven cases with 4p deletion and to assess the utility of Multiplex ligation-dependent probe amplification (MLPA) (cheap and sensitive test)-combined kits-as a diagnostic test and selection tool for cases that require other investigations (chromosomal microarray analysis-CMA, karyotype). For all cases we conducted a clinical examination with the main features identified: facial dysmorphism, intellectual disability, postnatal development delay, cardiac defects and hypotonia. In some cases, we observed seizures, structural brain abnormalities, immunodeficiencies, and renal anomalies. Prenatal growth retardation was detected in a relatively small number of cases, but postnatal growth failure was a constant feature. In all cases, the clinical diagnosis was confirmed by genetic analyses: karyotype and/or MLPA. In conclusion, renal and brain defects, as well as immunodeficiency are rare manifestations and should be looked for. Although CMA is the standard test, in our experience, MLPA is also a reliable screening method as the identified cases were either confirmed by MLPA or selected for further investigations.

Pallister-Killian Syndrome versus Trisomy 12p-A Clinical Study of 5 New Cases and a Literature Review.

Pallister-Killian syndrome (PKS) is a rare, sporadic disorder defined by a characteristic dysmorphic face, pigmentary skin anomalies, intellectual disability, hypotonia, and seizures caused by 12p tetrasomy due to an extra isochromosome 12p. We present three cases of PKS and two cases of trisomy 12p to illustrate and discuss features rarely cited in the literature, present certain particularities that not yet been cited, and analyze the differences between entities. Moreover, we present alternative methods of diagnosis that could be easily used in daily practice. Features not yet or rarely reported in PKS literature include marked excess of hair on the forehead and ears in the first months of life, a particular eye disorder (abnormal iris color with pointed pupil), connective tissue defects, repeated episodes of infection and autonomic dysfunction, endocrine malfunction as a possible cause of postnatal growth deficit, more complex sensory impairments, and mild early myoclonic jerks. After performing different combinations of tests, we conclude that MLPA (follow-up kit P230-B1) or array CGH using DNA extracted from a buccal swab is a reliable method of diagnosis in PKS and we recommend either one as a first intention diagnostic test. In cases without major defects associated (suspicion trisomy 12p), subtelomeric MLPA should be performed first.

Phenotypic variability in Patau syndrome.

UNLABELLED: Patau syndrome has an incidence of 1/10.000-20.000, the clinical diagnosis being suggested by the triad cleft lip and palate, microphthalmia/anophthalmia and postaxial polydactyly. Most frequent cytogenetic abnormality is free and homogeneous trisomy 13 (80.0%), rarely being detected trisomy mosaics or Robertsonian translocations. The objective of the study was to identify phenotypic features of trisomy 13. MATERIAL AND METHODS: The retrospective study was conducted on a trial group of 14 cases diagnosed cytogenetically with trisomy 13 between January 2000 and December 2012 at lasi Medical Genetics Centre. RESULTS: Of the 14 cases, 3 were evaluated pathologically (two aborted foetuses and one stillborn), 8 cases were detected in the neonatal period, and 3 in infancy. Clinical diagnosis was supported by the identification of a model of abnormal development, mainly characterized by: maxillary cleft (lip and palate--5 cases; lip--1 case), ocular abnormalities (microphthalmia/anophthalmia--7 cases; cyclopia--1 case), postaxial polydactyly (7 cases), scalp defects (6 cases), congenital heart anomalies (10 cases, 6 patients with atrial septal defect), complete holoprosencephaly (4 cases), ear abnormalities (11 cases), broad nasal root (10 cases). An important issue in confirming the phenotypic variability of Patau syndrome is that the classic clinical triad was identified only in one case. CONCLUSIONS: Patau syndrome is a disease with variable expression and is characterized by a pattern of abnormal prenatal development characterized by facial dysmorphia, polydactyly and severe birth defects (heart, brain) that generate an increased in utero and perinatal mortality.

Genotype- phenotype correlation in trisomy X: a retrospective study of a selected group of 36 patients and review of literature.

UNLABELLED: Trisomy X (47,XXX) is a gonosomal aneuploidy characterized by the presence of an extra X chromosome in a female person. Usually the diagnosis is established made postnatally by chromosome analysis in patients with suggestive clinical signs. Clinical signs vary by age. In prepubertal patients have a growth retardation associated with uncharacteristic facial dysmorphism, mild mental retardation with behavioral disorders, plus clinical signs of ovarian dysgenesis, postpubertal. AIM: We analyzed retrospectively the genotype - phenotype correlations for a selected group of 36 patients diagnosed with trisomy X (homogeneous or mosaic) by cytogenetic methods (X chromatin and karyotype). MATERIAL AND METHODS: Analysis of the clinical data of 36 patients diagnosed with trisomy X and correlation with the results of X chromatin and karyotype. RESULTS: Clinical signs detected in patients with homogeneous trisomy X 47,XXX (22.22%), mosaic 46,XX/47,XXX (16.66%) or 47,XXX/48,XXXX (5.55%) were prepubertal, growth retardation associated with dysmorphic facial (upslanted palpebral fissure, epichantus, thin lips) and postpubertal, signs of ovarian dysgenesis (secondary amenorrhea, early menopause). The phenotype of patients with different gonosomal mosaic corresponding to Turner syndrome, incorporating a cell line with trisomy X (55.55%) was variable, correlated with the type of chromosomal abnormalities detected. CONCLUSIONS: The results of our study are similar to those obtained in other studies and emphasizes that phenotypic variability of patients with trisomy X feature makes it difficult to genotype - phenotype correlations.

Inverted duplication deletion of 8P: characterization by standard cytogenetic and SNP array analyses.

Inverted 8p duplication deletions are recurrent chromosomal rearrangements that most often arise through non-allelic homologous recombination (NAHR) during maternal meiosis between segmental duplications made up of the olfactory receptor (OR) gene clusters. The presence of a paracentric inversion polymorphism in 8p23.1, found in approximately 26% of European population, may trigger meiotic misalignment and NAHR between the OR gene repeats. We report clinical, cytogenetic, and molecular findings in a 4 year 8 month-old female with concomitant inverted duplication and terminal deletion of chromosome 8p. The girl, the first child of unrelated parents, was born at term, by normal delivery, after an uneventful pregnancy. Clinical examination revealed dysmorphic features, pectus excavatum, hypertonia, severe developmental delay. Brain ultrasound and MRI showed agenesis of the corpus callosum without other abnormalities. Conventional cytogenetic analysis identified additional material on chromosome 8 at band p21. SNP array analysis further characterized the abnormality as a duplication of about 31.3 Mb, from 8p23.1 to 8p11.1, and additionally revealed a terminal deletion of about 6.8 Mb, from 8p23.3 to 8p23.1. Genomic microarray also identified a region of disomy between deletion and duplication. Chromosome analysis of both parents revealed normal results. Based on clinical examination, conventional cytogenetics and SNP array, we established the diagnosis of inverted duplication deletion of 8p. SNP array analysis precisely defined the breakpoints of rearrangement and, by identifying a region of disomy between the duplication and deletion, indicated that NAHR between segmental duplications was the most likely mechanism for this type of abnormality.

[Improvement of genetic diagnostic strategy in velo-cardio-facial syndrome]. / Optimizarea strategiei de diagnostic genetic în sindromul velo-cardio-facial.

UNLABELLED: Velo-Cardio-Facial Syndrome (VCFS) is characterized by congenital heart defects (CHD), palatal abnormalities, facial dysmorphism, neonatal hypocalcemia, immune deficit, speech and learning disabilities. SVCF is caused by microdeletion 22q11.2. Microdeletion is detected by fluorescence in situ hybridization (FISH). The highly variable phenotype makes diagnosis and selection for FISH more difficult. AIM: To retrospectively analyze and compare the phenotype of children with a clinical diagnosis of VCFS with/without 22q11 deletion; to verify the validity of literature guidelines and to describe combinations of clinical features that should lead to molecular analysis. MATERIAL AND METHODS: The present study was performed in 21 patients with a clinical diagnosis of VCFS. Methaphase chromosome spreads were prepared from phytohaemagglutinin stimulated lymphocyte culture by standard methods before FISH. The patients were divided into two groups according to FISH test: positive and negative. RESULTS: The features commonly noticed in FISH positive patients were: palatal abnormalities/hypernasal speech, learning disabilities, facial dysmorphism, tapered fingers (6/6), CHD (5/6) and recurrent infections (2/6). In FISH negative patients the following were found: learning disabilities, CHD (12/15); facial dysmorphism (10/15), family history of CHD (7/15), short stature (6/15), hypocalcemia, tapered fingers (5/15), recurrent infections (3/15) and palatal cleft (2/15). In both groups, Tobias and McDonald-McGinn guidelines were positive. CONCLUSIONS: VCFS has a highly variable phenotype. Our study suggests that 22q11.2 deletion analysis by FISH should be performed in patients who have at least 2 (newborn)/3 (child, adult) specific criteria: CHD, hypocalcemia, palatal abnormalities, facial dysmorphism, learning disabilities, digital anomalies, and immune deficit.

[Chromosomal evaluation in couples with reproductive disorders--retrospective study of a selected group of 266 couples]. / Evaluarea cromozomiala a cuplurilor cu tulburari de reproducere--studiu retrospectiv pe un lot selectionat de 266 cupluri.

UNLABELLED: Reproductive Disorders (RD), manifested by the biological inability to conceive (primary sterility) or inability to carry a pregnancy to full-term (infertility), affect 10-15% of reproductive-aged couples. The genetic etiology of RD is represented, in the majority of cases, by the chromosomal abnormalities. AIM: To retrospectively analyze the karyotype results in a selected group of couples with RD. MATERIAL AND METHOD: The present study was performed in 266 couples with RD: 80 (30.07%) with primary sterility (ST), 149 (56.01%) with Recurrent Spontaneous Abortions (RSA) and 37 (13.90%) with Stillborn Children (SC). A GTG-banded karyotype was performed on both partners of each couple. RESULTS: We identified a chromosomal abnormality in 43 individuals (16.16%): 20 cases (7.51%) with ST, 13 cases (4.88%) with RSA and 10 cases (3.75%) with SC. The affected partner was female in 23 cases (8.64%) and male in 20 cases (7.51%). A X chromosome (numerical or structural) abnormality was detected in 18 cases (6.76%), most frequent X chromosome monosomy mosaicism in female and trisomy XXY in male; a balanced structural chromosomal abnormality (BSC) was detected in 23 couples (8.64%); in other two males with ST, the karyotype result was 46,XX. CONCLUSIONS: The results of our study are similar to other reported studies and underline the major etiologic role of chromosomal abnormalities in RD and the importance of chromosomal analysis for the etiologic diagnosis and genetic counseling of these patients.

[Use of MLPA test in the detection of subtelomeric rearrangements--case report]. / Utilitatea testului MLPA in depistarea rearanjamentelor subtelomerice--discutii pe marginea unor cazuri de retard mintal idiopatic.

Genetic causes of mental retardation (MR) are heterogeneous, but subtelomeric rearrangements are an important one. MLPA technique provides the best results in case detection. We have used MLPA to identify subtelomeric rearrangements in children with idiopatic MR. The protocol included: clinical selection; karyotype; antiFMRP test; MLPA. We have selected cases using de Vries diagnostic score. Patient data were recorded in a database. The group was formed of 142 MR children. In 24 (16.9%) the karyotype was abnormal. 16 cases (11.3%) presented speech delay/autism, but antiFMRP test was normal. 60 MLPA tests were done: 46 cases (76.7% were normal, 6 (10%) abnormal, 4 (6.7%) had polymorphism and 4 (6.7%) could not be interpreted. Clinical features of the cases identified are illustrated. In conclusion, the diagnostic score is useful in case selection for further testing and MLPA proves to be efficient in diagnosing subtelomeric rearrangements as a possible cause of idiopatic MR.

[Idiopathic mental retardation--importance of clinical diagnostic scores for case selection]. / Retardul mental idiopatic--importanta scorurilor de diagnostic clinic pentru selectia cazurilor.

We present a retrospective study aimed to identify the correlation between de Vries clinical score and the detection of chromosomal abnormalities in mentally retarded (MR) children. We have used the score to identify patients who should be tested by karyotyping and subsequently MLPA (multiplex ligation dependent probe amplification) for subtelomeric rearrangements. Our group is formed of 36 children with variable MR associated with other anomalies. 18 children had chromosomal defects, whereas 18 had normal karyotypes. In the first group, total scores varied between 3 and 7. Chromosomal anomalies identified were: numerical (4) and structural (14). Chromosomes involved were: 1, 4, 5, 7, 8, 9, 17, X. Deletions were the most common and correlate with a greater score (> or = 4). Common clinical features were: short stature, microcephaly, nasal, ear and hand anomalies. In the second group the most frequent clinical feature was hand anomaly (61.2%) and cases with a high score have to be further tested (e.g. using MLPA) in order to identify minor defects. In our opinion a high score indicates the karyotype and then a MLPA testing. In conclusion, we present a retrospective study that proves the use of de Vries diagnostic score in the identification of chromosomal abnormalities in MR children.