SMA prenatal diagnosis: a modified protocol to help differentiation between deletions and gene conversion.

In SMA, unusual findings such as deletions restricted only to SMN1 exon 8, inspite of honozygous SMN1 exons 7-8 deletions in the family, may obscure final diagnosis. Application of a modified PCR procedure allowed discrimination between a deletion or a gene conversion event in a case of prenatal diagnosis.

PGD for X-linked and gender-dependent disorders using a robust, flexible single-tube PCR protocol.

X-linked genetic diseases include a wide range of disorders such as the dystrophinopathies. Additionally in some rare genetic diseases, severity of expression is gender dependent. Prevention of such disorders usually involves prenatal diagnosis and termination of affected pregnancies, while preimplantation genetic diagnosis (PGD) represents a specialized alternative that avoids pregnancy termination. To preclude the rejection of unaffected male embryos that cannot be differentiated from those affected when using fluorescence in-situ hybridization, a flexible protocol based on multiplex fluorescence polymerase chain reaction (PCR) was standardized and validated for gender determination in single cells, which can potentially incorporate any disease-specific locus. The final panel of nine loci included four loci on the Y chromosome, two on the X chromosome plus up to three microsatellite markers to either support the gender diagnosis or to further monitor extraneous contamination. The protocol, standardized on single lymphocytes, established a PCR efficiency of >93% for all loci with maximum allele dropout rates of 4%. Microsatellite analysis excluded external contamination and confirmed biallelic inheritance. Proof of principle for the simplicity and flexibility of the assay was demonstrated through its application to clinical PGD cycles for lipoid congenital adrenal hyperplasia, which presents a more severe clinical course in males, and Duchenne muscular dystrophy.

Association of repeat polymorphisms in the estrogen receptors alpha, beta (ESR1, ESR2) and androgen receptor (AR) genes with the occurrence of breast cancer.

Genetic variation in genes involved in estrogen biosynthesis, metabolism and signal transduction have been suggested to play a role in breast cancer. To determine the possible contribution of genetic variation in the ESR1 (ER-alpha), ESR2 (ER-beta) and AR genes in breast cancer risk the -1174(TA)(7-27), c. 1092+3607(CA)(10-26) and c. 172(CAG)(6-40) repeat variants were studied in a case-control study of 79 women with sporadic breast cancer and 155 controls. No significant difference was observed in the frequency distribution of -1174(TA)(7-27) in the ESR1 gene between patients and controls, while a significant difference was observed for repeat polymorphisms c. 1092+3607(CA)(10-26) in the ESR2 gene and c. 172(CAG)(6-40) in the AR gene (p0.0001). A significantly decreased odds ratio (OR) for breast cancer risk was observed in individuals having the LL and the SL genotypes for both the ESR2 (OR=0.010, 95% CI 0.003-0.036, p<0.001; OR=0.013, 95% CI 0.004-0.040, p<0.0001, respectively) and the AR gene (OR=0.040, 95% CI 0.011-0.138, p<0.0001; OR=0.189, 95% CI 0.10-0.359, p<0.0001, respectively), compared to SS genotype. The protective effect of these genotypes remained evident even after adjustment for various risk factors (BMI, age, age at menarche and menopause, family history). In conclusion, an association for breast cancer risk between short (SS) alleles for the repeat variants of the ESR2 and AR genes was found in women of Greek descent.

10 years' experience in fragile X testing among mentally retarded individuals in Greece: a molecular and epidemiological approach.

Fragile X syndrome, the second most common genetic cause of mental retardation, is due to the expansion of a trinucleotide repeat (CGG)n within the first exon of the FMR-1 gene. Molecular genetic analysis provides accurate diagnosis and facilitates genetic counselling and prenatal testing. Screening for the fragile X mutation in a sample of 3,888 individuals in Greece is reported: 1,755 children with non-specific mental retardation, 1,733 parents and other family members and 400 normal individuals. Molecular analysis allowed for the identification and characterization of 52 fragile X families confirming the clinical diagnosis in 57 males and 4 females. Sixty-six female carriers (6 mentally retarded) and 4 normal transmitting males were also identified. Four severely retarded males and their mothers carried unmethylated premutations, while a moderately retarded girl had a deletion of approximately equal to 150 bp. Overall sizing of the CGG repeat produced an allele distribution of 6-58 CGG repeats (mean 28-30), similar to that in other Caucasian populations.

Complex rearrangements of chromosome 15 in two patients with mild/atypical Prader Willi syndrome.

Multiple mechanisms are responsible for the development of Prader Willi syndrome (PWS), the most common genetic cause of obesity in childhood. Molecular findings are usually deletions and uniparental disomy (UPD) of the 15q11-13 region. Rarely, structural rearrangements of the pericentromeric region of chromosome 15 are also detected. Two cases with mild PWS phenotype and complex maternal UPD identified by microsatellite analysis are described: the first patient had uniparental iso and heterodisomy and the second displayed biallelic inheritance and uniparental isodisomy.

Coinheritance of mutated SMN1 and MECP2 genes in a child with phenotypic features of spinal muscular atrophy (SMA) type II and Rett syndrome.

Spinal muscular atrophy (SMA) is a neuromuscular autosomal recessive disease characterized by progressive muscle weakness and atrophy combined with motor neuron degeneration caused by mutations in the SMN 1 gene locus (5q11.2-13.2). Rett syndrome (RS) is an X-linked dominant neurodevelopmental disorder caused by mutations in MECP2 (Xq28) and characterized by normal development until 6-12 months of age, followed by regression with loss of acquired skills, gradual onset of microcephaly, stereotypic hand movements and psychomotor delay. We report a 6-year-old girl who, at 2 years of age, presented with hypotonia, psychomotor delay, amyotrophy and areflexia of the lower extremities. Molecular DNA analysis (PCR-RFLP's) for SMA type II revealed that both exons 7 and 8 of SMN 1 gene were deleted. Over the past 4 years, onset of stereotypic hand-washing movements, epileptic seizures, microcephaly, hyperventilation/breath-holding attacks and severe psychomotor delay raised the suspicion of the coexistence of RS. DNA analysis (DGGE and sequencing) identified the hotspot missense mutation R306C (c.916C>T) in exon 4 of the MECP2 gene. The coinheritance of SMA and RS, two rare monogenic syndromes in the same patient, has not been previously reported. Thorough clinical evaluation in combination with DNA analysis, allowed accurate diagnosis, providing valuable information for the genetic counseling of the family.

Clinical expression of co-inherited Dubin-Johnson and thalassaemic heterozygous states.

Dubin-Johnson syndrome is a worldwide prevalent familial conjugated hyperbilirubinaemia. The identification of multidrug resistance-associated protein 2 provided an understanding of the complex metabolic impairment involved in this syndrome. We report the first family with modified clinical expression of Dubin-Johnson heterozygous state due to genotypic interaction with co-inherited beta and deltabeta thalassaemia, an interaction that has never been described.

Identification of autosomal supernumerary chromosome markers (SMCs) by fluorescent in situ hybridization (FISH).

Supernumerary marker chromosomes (SMCs) are rare chromosomal abnormalities resulting in partial trisomy of specific genomic regions with characteristic phenotypic effects. Twenty six cases with autosomal SMCs are reported. Four were identified prenatally and 22 postnatally in children, aged from 8 days to 15 years, who were referred for genetic evaluation because of various congenital anomalies and developmental delay. In 22 of the 26 cases, the SMCs were de novo, in two they were familial and in another two a 11;22 reciprocal translocation was revealed in the mothers. In only one patient was the SMC present in a mosaic form. Sequential fluorescent in situ hybridization studies (FISH) using Whole Chromosome Paint (WCP) probes were performed in order to determine the chromosomal origin of the SMCs. Sixteen of them originated from chromosome 15, five were shown to be an isochromosome 18p and one was derived from chromosome 22, but did not contain the DiGeorge/ VCFS critical region. In two instances, the SMCs were derivatives of chromosome 13 and in two the SMCs resulted from a 11;22 maternal translocation and contained material from both chromosomes 11 and 22. Molecular investigation of two of the patients with an SMC[15] revealed three copies of the SNRPN gene, but the diagnosis of PW/AS due to possible imprinting was excluded in both patients by a methylation-specific PCR. FISH and molecular studies have greatly facilitated the characterization of marker chromosomes. As more SMCs are classified, better genetic counseling and risk evaluation can be achieved.

A case of Ehlers Danlos syndrome type VI.

Ehlers Danlos type VI is a rare autosomal recessive connective tissue disease involving primarily the skin and joints. The main feature of the condition is neonatal hypotonia and rare complications are ruptures of arteries and the eye globe. A 4 year old girl with a typical clinical presentation and molecular diagnosis of EDS VI is presented. Sequencing of PLOD1 gene revealed a homozygous deletion in exon 13 (c.1362delC), leading to a frameshift and truncation of the lysyl hydroxylase, an enzyme necessary for collagen biosynthesis. Early diagnosis allowed treatment with high doses of ascorbic acid in order to prevent complications, genetic counseling of the family and prenatal diagnosis of an unaffected embryo.

Impact of cytogenetic and molecular cytogenetic studies on hematologic malignancies.

Conventional cytogenetic analysis of chromosome abnormalities in hematologic malignancies is hampered by the low mitotic index and poor quality of metaphases. A range of techniques based on fluorescence in situ hybridization (FISH) has greatly enhanced the identification of non-random translocations and deletions, pinpointing regions which contain genes involved in leukemogenesis. One of the main advantages of FISH is its ability to use non-dividing interphase cells as DNA targets, enabling the screening of large numbers of cells and providing access to a variety of cells with different hematopoetic activity. Furthermore, multicolor FISH (SKY, M-FISH and CGH microarrays) combines the screening potential of cytogenetics with the accuracy of molecular genetics, allowing the visualization of the entire human genome in 24 different colors.

Tetrasomy 18p de novo: parental origin and different mechanisms of formation.

We have used eight PCR-based DNA polymorphisms to determine the parental origin and mechanisms of formation in 9 patients with de novo nonmosaic tetrasomy 18p. The 9 patients, 4 girls and 5 boys, had clinical features characteristic of i(18p) syndrome. The supernumerary marker chromosome was identified by fluorescence in situ hybridization (FISH) analysis using centromeric probes and a flow-sorted 18p-specific library. The isochromosome was of maternal origin in all 9 cases. The formation of tetrasomy 18p cannot be explained by a single model. In 6 cases, meiosis II nondisjunction, followed by subsequent postzygotic misdivsion, and in 1 case postzygotic nondisjunction and postzygotic misdivision were the most likely mechanisms of formation. Alternative mechanisms are suggested in the remaining 2 cases.

Severe proteus syndrome in an 18-month-old boy.

We describe an 18-month-old Greek boy with macrocephaly, partial gigantism of hands and feet, hemihypertrophy, pigmented nevi, and other anomalies compatible with the Proteus syndrome. Cerebral involvement in a most severe form and at an early age concurs with the suggestion that encephalocraniocutaneous lipomatosis may represent a more circumscriptive manifestation of Proteus syndrome. Localized triggering of several growth factors is a challenging pathogenetic consideration of the syndrome.

Molecular cytogenetic characterization and origin of two de novo duplication 9p cases.

We report on two additional cases with duplication of 9p, minor with facial anomalies and developmental delay. Using fluorescence in situ hybridization and single-copy probes, we showed that the first case was a direct duplication, whereas the second case was inverted. The extent of the direct duplication was defined as 9p12 --> p24 by microdissection and microcloning of the aberrant chromosome and subsequent chromosome-specific comparative genomic hybridization. DNA polymorphism analysis with eight microsatellite markers revealed that the origin of the dup(9p) was maternal in the first case, whereas it was paternal in the second.

Two-way trafficking of Annexin V positive cells between mother and fetus: determination of apoptosis at delivery.

OBJECTIVES: The aim of this study was to quantitate apoptosis in maternal circulation and umbilical cord blood (UCB) at delivery. The proportion of fetal cells in maternal blood as well as that of maternal cells in UCB was also determined. MATERIAL AND METHODS: Three milliliters of peripheral blood was collected from nine women during labor. Five women delivered males and four delivered females. Immediately after delivery, 3 mL UCB was collected. Ten microliters was used to quantitate apoptosis by the ethidium bromide assay (EthBr) and from the remaining blood, Annexin V positive cells were isolated by MACS. RESULTS: The Median apoptosis rate in maternal samples was 25% (19-34) and in UCB 20% (16-28). Annexin V positive cells were present in all samples analyzed. As shown by Fluorescence in situ hybridization (FISH) in maternal samples, cells with an XY hybridization pattern were identified in cases with male newborns in a median concentration of 1.7% (1.6-2.1). On the corresponding UCB, a median of 1.2% (0.8-1.6) XX cells were detected. CONCLUSION: The study demonstrates the existence of a bidirectional transfer of fetal and maternal cells under apoptosis across the placenta and provides useful information regarding use of UCB for transplantation.

Glucose-6-phosphate dehydrogenase deficiency and Gilbert syndrome: a gene interaction underlies severe jaundice without severe hemolysis.

The authors describe the paradoxical clinical phenotype of an undetected severe hemolysis in parallel with the development of severe jaundice in a 13-year-old male suffering from a confirmed interaction of glucose-6-phosphate dehydrogenase deficiency (Mediterranean variant, 563 C/T) and Gilbert syndrome [variant (TA)7/(TA)7]. The child had 2 acute hemolytic episodes at the age of 10 and 13 years following infections of unknown origin. Both episodes were characterized by considerably high bilirubin levels (1st episode: 10.8 mg/dL, 2nd episode: 17.8 mg/dL) associated with unexpectably mild hemolysis indices (1st episode hemoglobin levels, 11.1 g/dL; reticulocyte counts, 2.5%; 2nd episode hemoglobin values, 12.7 g/dL; reticulocyte counts, 2.5%). During the steady-state condition of the child, hemoglobin values were within the normal ranges for his age (14.2 g/dL) and bilirubin levels were slightly elevated (1.70 mg/dL, indirect 1.5 mg/dL). The interaction of the two genetic abnormalities in the causation of this odd clinical phenotype is discussed.

Unusual pathologic findings in a girl with Wolf-Hirschhorn syndrome, del (4p).

A newborn girl with Wolf-Hirschhorn syndrome and 46, XX, del (4) (p15) de novo karyotype is described. Unusual pathologic and histologic findings were observed at autopsy in the cardiovascular, respiratory, alimentary, and urogenital systems. Of over 100 cases reported in the literature, only 18 include pathologic findings.

[Polymorphism of restriction fragment length in the detection of the precise status of monosomy 21 in a deformed retarded girl]. / Etude des polymorphismes de la longueur des fragments de restriction afin de détecter l'état précis de la monosomes 21 d'une fillette malformée et retardée.

The authors used genomic single copy DNA fragments cloned from chromosome 21 to study cytogenetic abnormalities in patients not easily defined by conventional cytogenetic means. Ten restriction fragment length polymorphisms (RLFP) detected by 8 independent probes were used to detect homologous sequences from chromosome 21 in genomic digests of DNA from one patient and her parents. The proband is a 3 1/2-year-old girl who was referred to us at 1 month of age because of hypertonia, hirsutism, flattened nasal bridge, antimongoloid slant of palpebral fissures, high arched palate and bilateral hip dysplasia. The karyotype of the proband was: 46, XX, -3, -21, + ? del (3) (3 pter----3q1:) +? (3qter----3q1:: 21q21----21 pter). GTG banding and the karyotype of her parents were normal (in peripheral blood and skin fibroblasts). She was re-examined by us every three months, because she showed physical and psychomotor retardation. We traced the inheritance of RFLPs from her parents, and familial molecular studies showed in contrast to the cytogenetic analysis that the patient is disomic for all regions of 21q tested by our collection of probes. The use of molecular technology has resulted in a more precise definition of 21 chromosome abnormalities and especially the "complete" monosomy 21 which is extremely rare in live born infants.

Splenic granulomatous lesions in immunocompetent pediatric patients with visceral leishmaniasis.

Visceral focal lesions are rarely encountered in patients with leishmaniasis despite the fact that splenomegaly, and to a lesser extent hepatomegaly, predominate among the clinical features of the disease. We present, using high resolution ultrasonography, the first 3 reported cases of focal splenic involvement in immunocompetent children with visceral leishmaniasis. All patients showed a prompt response to the conventional anti-leishmanial treatment administered. This favorable outcome indicates that localized splenic lesions should not be considered as a poor prognostic factor and that alteration of the standard anti-leishmanial regimens is not justified.

Antepartum aminophylline treatment for prevention of the respiratory distress syndrome in premature infants.

The frequency of idiopathic respiratory distress (IRD) among premature offspring born of women who were given aminophylline before the thirty-fourth week of pregnancy was evaluated. Sixty-seven premature deliveries were included in the aminophylline group and 75 in the control group. The perinatal death rate was 7.1% in the aminophylline group and 17.9% in the control group (p less than 0.05). A statistically significant difference was noted between the aminophylline and control groups in the frequency of IRD which was three times lower (10%) in the aminophylline group than in the control group (29.5%) for the total of premature infants. If the time of rupture of membranes is taken into consideration, a significant decrease in the frequency of IRD following aminophylline administration is noted in the infants, whose mothers had ruptured membranes for more than 24 hours. No complications or side effects of aminophylline administration were noted in the mothers or their infants.