Cristina Rusu

Identifying Down Syndrome Cases by Combined Use of Face Recognition Methods

Down syndrome is a chromosomal disorder, people affected by this disease having very specific facial characteristics. In this paper we adapt some well-known face recognition methods (Local Binary Patterns, Eigenfaces) and test their ability to distinguish between a Down syndrome face and a normal one in digital images. For classification kNN (k Nearest Neighbor) and Support Vector Machines (SVM) with polynomial kernel of third degree and Radial Basis Function (RBF) are employed. We test the methods using FERET, CAS-PEAL, LFW, AT&T for normal face images and a collection of Down faces gathered from the Internet. Accuracy, precision, recall and specificity are computed in order to evaluate the classification results.

Detection of chromosomal imbalances using combined MLPA kits in patients with syndromic intellectual disability

Abstract Intellectual disability (ID) is a common disorder, with major consequences for individual, family and society. Due to clinical and genetic heterogeneity of ID, in about 50% of cases an etiologic diagnosis cannot be established. The aim of this study was to evaluate the ability of a combination of MLPA kits to establish the diagnosis in 369 patients with syndromic ID and normal or uncertain routine karyotype results. All patients were assessed for chromosome imbalance using SALSA MLPA P064 or P096 kits, if the phenotype was suggestive of a microdeletion syndrome (subgroup A - 186 patients), or subtelomeric P036 and P070 kits, if the phenotype was not suggestive of a microdeletion syndrome or if the result of the standard karyotype was uncertain (subgroup B - 183 patients). Abnormal results detected by these kits were further characterized using appropriate follow-up MLPA kits (Telomere Follow-up set, P029-A1, P250-B2, ME028-B1). In subgroup A we identified 25 patients with microdeletions (13.4%). Using subtelomere screening and follow-up kits in subgroup B we detected cryptic rearrangements in 7.5% cases and identified the origin of the unknown material noticed in the standard karyotype in 10 out of 11 patients. Summarizing data from the two groups, the combined use of MLPA kits led to the diagnosis in 10.6% (38/358) patients with normal karyotype. Using follow-up MLPA kits allowed us both to confirm abnormalities and to determine their size, which facilitated the interpretation of the clinical significance of these rearrangements. For laboratories that do not have yet access to microarray technology, using several MLPA kits represents an effective strategy for establishing the diagnosis in ID patients. Rezumat Dizabilitatea intelectuală (DI) este o afecțiune frecventă, cu consecințe majore pentru individ, familie și societate. Datorită heterogenității sale clinice și genetice, în aproximativ 50% din cazuri etiologia bolii nu poate fi stabilită. Scopul acestui studiu a fost evaluarea capacității de stabilire a diagnosticului etiologic la 369 pacienți cu DI sindromic și rezultat normal sau incert la cariotip folosind o combinație de kituri MLPA. Toţi pacienţii au fost investigaţi prin metoda MLPA, folosind fie kiturile SALSA MLPA P064 sau P096, dacă fenotipul a fost sugestiv pentru un sindrom cu microdeleţie (subgrupul A - 186 pacienți), fie kiturile subtelomerice P036 și P070, dacă fenotipul nu a fost sugestiv pentru un sindrom cu microdeleţie sau rezultatul la cariotipul standard a fost incert (subgrupul B - 183 pacienți). Rezultatele anormale detectate de aceste kituri au fost caracterizate folosind kiturile MLPA corespunzătoare de urmărire (Telomere Follow-up set, P029-A1, P250-B2, ME028-B1). În subgrupul A am identificat 25 de pacienți cu microdeleții (13,4%). Folosind kiturile de screening subtelomeric și de urmărire la subgrupul B am detectat rearanjări criptice în 7,5% din cazuri și am identificat originea materialului suplimentar observat la cariotipul standard la 10 din 11 pacienți. Sumarizând datele obţinute din cele două loturi, folosirea combinată a seturilor MLPA a dus la stabilirea diagnosticului la 10,6% (38/358) dintre pacienții cu cariotip normal. Folosirea seturilor MLPA de urmărire a permis atât confirmarea prezenţei anomaliei, cât şi determinarea dimensiunii ei, ceea ce a facilitat interpretarea semnificaţiei clinice a rearanjărilor. Pentru laboratoarele care nu au acces la tehnologiile bazate pe microarray, folosirea mai multor kituri MLPA reprezintă o strategie eficientă pentru stabilirea diagnosticului etiologic la pacienţii cu DI.

Identification of Exonic Copy Number Variations in Dystrophin Gene Using Mlpa / Identificarea Variaţiilor Numărului de Copii în Gena Distrofinei Folosind Metoda Mlpa

Abstract Duchenne and Becker muscular dystrophies (DMD/BMD) are X-linked progressive muscle disorders determined by mutations of the dystrophin (DMD) gene. Multiplex Ligation - Dependent Probe Amplification (MLPA) is a simple, inexpensive and reliable test for molecular diagnosis of DMD gene mutations. It identifies exonic copy number variations in the DMD gene, but the test should be completed with sequencing analysis in case of single exon deletions/duplications. The aim of this study was to evaluate the efficiency of MLPA as a DMD mutation screening tool in affected males and carrier females, as well as to appreciate the frequency of different types of mutations and to check the validity of the “reading frame rule”. We have used MLPA for the detection of deletions/ duplications in DMD gene in 53 individuals (30 affected males and 23 asymptomatic female relatives) referred for evaluation and genetic counseling due to the clinical suspicion of DMD/BMD. In the affected males (21 DMD and 9 BMD) MLPA had a detection rate of 63.5% (53.5% deletions and 10% duplications). The most frequently deleted exon was exon 45 and the most frequent duplication involved exons 3-5, confirming the presence of the two hotspot mutation regions reported in the literature. Mutations detected in our study have a slightly different location compared to literature data. Reading frame rule was valid in 84% of our cases. Rezumat Distrofiile musculare Duchenne şi Becker (DMD/BMD) sunt boli musculare progresive legate de X determinate de mutaţii în gena distrofinei (DMD). Multiplex Ligation - Dependent Probe Amplification (MLPA) este o metodă simplă, necostisitoare şi precisă pentru diagnosticul molecular al mutaţiilor genei DMD. Ea identifică variaţiile numărului de copii în gena distrofinei, dar trebuie completată cu secvenţierea genei în cazul identificării deleţiilor/duplicaţiilor unui singur exon. Scopul acestui studiu a fost de a evalua eficienţa MLPA ca test de screening al mutaţiilor în gena DMD la indivizii afectaţi şi femeile purtătoare, dar şi de a aprecia frecvenţa diferitelor tipuri de mutaţii şi de a verifica valabilitatea “regulii cadrului de lectură. Am folosit MLPA pentru detectarea deleţiilor/ duplicaţiilor în gena DMD la 53 indivizi (30 băieţi afectaţi şi 23 rude asimptomatice de sex feminin) trimişi pentru evaluare şi sfat genetic datorită suspiciunii clinice de DMD/BMD. La băieţii afectaţi (21 DMD şi 9 BMD) MLPA a avut o rată de detecţie de 63,5% (53,5% deleţii şi 10% duplicaţii). Cel mai frecvent deletat exon a fost exonul 45 şi cea mai frecventă duplicaţie a implicat exonii 3-5, confirmând prezenţa celor două regiuni critice mutaţionale raportate în literatură. Mutaţiile detectate în studiul nostru au avut o localizare uşor diferită comparativ cu datele din literatură. Regula cadrului de lectură a fost valabilă în 84% din cazuri.

The neuro-cardio-facial-cutaneous syndrome – unity in diversity

The neuro-cardio-facial-cutaneous syndrome (NCFCS) concept was recently established in order to group a number of hereditary disorders characterized by a variable degree of growth and mental retardation, cardiac defects, dysmorphic facial features and skin abnormalities, and having a common background, germline mutations in genes of the RAS-MAPKinase pathway. The included entities are Noonan and Leopard syndrome (the most frequents), Costello syndrome, cranio-facio-cutaneous syndrome, as well as some forms of type 1 neurofybromatosis and the newly defined Legius syndrome. We present illustrative cases of 2 of this syndromes, Noonan (NS) and Leopard syndrome (LS), illustrative for both the common elements and the variety of the characteristics. Four of the six cases of Noonan syndrome are treated with growth hormone, with a good response, proving the importance of an early diagnostic. Two cases are fronm the same family (mother and son), the mother of another case has patognomic features but the diagnostic had not yet been confirmed. One of the children with NS, recently diagnosed, with important vertebral deformation needing specific treatment cannot, for the moment, be treated with hGH in spite of the important growth delay (>-3SD). LEOPARD is an acronym for the major features of the disorder: Lentigines, ECG conduction abnormalities, Ocular hypertelorism, Pulmonary stenosis, Abnormal genitalia, Retardation of growth, Deafness. The probant case of LS, a 15 years old boy, presented almost all these features, with the exception of deafness. He associated a cerebral tumor, rare in LS, but which could be considered as a NCFCS feature, the MAPK pathway being involved in tumorigenesis. He presented with short stature and neurologic symptoms, both improved after the (partial) tumor resection (pylocytic astrocytoma). The genetic investigation of the family confirmed the syndrome at 4 other members (father, two brothers and a sister), each one with various manifestations, from only cafe-au-lait spots to cardiac malformations. The absence of patognomonic symptoms as well as the overlap of numerous features makes the diagnosis of the components of NCFCS difficult, the molecular diagnosis offering the chance to exceed the clinical difficulties. More than that, specific mutations are associated with specific fenotypes, which has a great importance for the diagnostic and prognostic. An early diagnostic is important not only for the rapid treatment of life threatening elements (cardiac malformations, tumors) and chronic treatment of some features (like short stature), but also for an appropriate genetic counseling.