Cobblestone lissencephaly: neuropathological subtypes and correlations with genes of dystroglycanopathies.

Cobblestone lissencephaly represents a peculiar brain malformation with characteristic radiological anomalies, defined as cortical dysplasia combined with dysmyelination, dysplastic cerebellum with cysts and brainstem hypoplasia. Cortical dysplasia results from neuroglial overmigration into the arachnoid space, forming an extracortical layer, responsible for agyria and/or 'cobblestone' brain surface and ventricular enlargement. The underlying mechanism is a disruption of the glia limitans, the outermost layer of the brain. Cobblestone lissencephaly is pathognomonic of a continuum of autosomal recessive diseases with cerebral, ocular and muscular deficits, Walker-Warburg syndrome, muscle-eye-brain and Fukuyama muscular dystrophy. Mutations in POMT1, POMT2, POMGNT1, LARGE, FKTN and FKRP genes attributed these diseases to α-dystroglycanopathies. However, studies have not been able to identify causal mutations in the majority of patients and to establish a clear phenotype/genotype correlation. Therefore, we decided to perform a detailed neuropathological survey and molecular screenings in 65 foetal cases selected on the basis of histopathological criteria. After sequencing the six genes of α-dystroglycanopathies, a causal mutation was observed in 66% of cases. On the basis of a ratio of severity, three subtypes clearly emerged. The most severe, which we called cobblestone lissencephaly A, was linked to mutations in POMT1 (34%), POMT2 (8%) and FKRP (1.5%). The least severe, cobblestone lissencephaly C, was linked to POMGNT1 mutations (18%). An intermediary type, cobblestone lissencephaly B, was linked to LARGE mutations (4.5%) identified for the first time in foetuses. We conclude that cobblestone lissencephaly encompasses three distinct subtypes of cortical malformations with different degrees of neuroglial ectopia into the arachnoid space and cortical plate disorganization regardless of gestational age. In the cerebellum, histopathological changes support the novel hypothesis that abnormal lamination arises from a deficiency in granule cells. Our studies demonstrate the positive impact of histoneuropathology on the identification of α-dystroglycanopathies found in 66% of cases, while with neuroimaging criteria and biological values, mutations are found in 32-50% of patients. Interestingly, our morphological classification was central in the orientation of genetic screening of POMT1, POMT2, POMGNT1, LARGE and FKRP. Despite intensive research, one-third of our cases remained unexplained; suggesting that other genes and/or pathways may be involved. This material offers a rich resource for studies on the affected neurodevelopmental processes of cobblestone lissencephaly and on the identification of other responsible gene(s)/pathway(s).

Impact of non-invasive fetal RhD genotyping on management costs of rhesus-D negative patients: results of a French pilot study.

OBJECTIVES: Fetal rhesus D (RhD) status determination using circulating cell-free fetal DNA from maternal plasma or serum is now recognized in Europe as a reliable and useful tool. A few countries are presently using this test in their management policy of rhesus D negative patients. The objective of this study is to evaluate the impact of this test on the costs of managing RhD-negative pregnant women, whether or not they are allo-immunized. STUDY DESIGN: A prospective follow-up of rhesus D negative women during their pregnancy was performed in three French obstetric departments. Non-invasive fetal RhD genotyping was performed in the first trimester and pregnancies were followed The costs of all procedures (biological tests and medication) associated with patient management in relation to their RhD-negative status were calculated according to different management options. RESULTS: A comprehensive follow-up, including medical and biological monitoring, was obtained for 99 of the 101 patients included in the study. Patients were separated into two groups: the "Adverse Event" group (AE, n=23) for which a potentially sensitizing event occurred and the "No Adverse Event" group (NAE, n=76). Fetal RhD status was accurately determined in all cases. The mean cost per patient was estimated at 237€ (range: 115-644) with differences observed depending on the group, notably 331€ (range: 236-644) for the AE group and 208€ (range: 115-366) for the NAE group. Various cost simulations were performed according to various policies of allo-immunization antenatal prophylaxis. Variations ranged from +36.2% to +105.3%. CONCLUSION: This study demonstrates that fetal RhD genotyping early during pregnancy is not an effective cost-reduction strategy whether or not antenatal prophylaxis is given. The economic issues could, however, be overcome by the fact that there is a major clinical benefit to offering the test systematically to all RhD-negative pregnant women while avoiding unnecessary testing and immunoglobulin injections.

Phenotypic spectrum of fetal Smith-Lemli-Opitz syndrome.

The Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive multiple congenital malformation syndrome caused by dehydrocholesterol reductase deficiency. The diagnosis is confirmed by high 7- and secondarily 8-dehydrocholesterol levels in plasma and tissues and/or by detection of biallelic mutations in the DHCR7 gene. The phenotypic spectrum of SLOS is broad, ranging from a mild phenotype combining subtle physical anomalies with behavioral and learning problems, to a perinatally lethal multiple malformations syndrome. The fetal phenotype of SLOS has been poorly described in the literature. We report a series of 10 fetuses with molecularly proven SLOS. Even in young fetuses, the facial dysmorphism appears characteristic. Genital abnormalities are rare in 46,XX subjects. Gonadal differentiation appears histologically normal and in agreement with the chromosomal sex, contrary to what has been previously stated. We observed some previously unreported anomalies: ulnar hypoplasia, vertebral segmentation anomalies, congenital pulmonary adenomatoid malformation, fused lungs, gastroschisis, holomyelia and hypothalamic hamartoma. This latter malformation proves that SLOS phenotypically overlaps with Pallister-Hall syndrome which remains clinically a major differential diagnosis of SLOS.

Nonvisualization of the fetal gallbladder by second-trimester ultrasound scan: strategy of clinical management based on four examples.

OBJECTIVE: When the fetal gallbladder is not seen at ultrasound (US) scan, to propose a diagnostic method of differentiating fetuses who are healthy or have minor anomalies from fetuses with severe anomalies requiring intensive management. METHOD: We present four clinical cases illustrating this variability, together with additional examinations: karyotyping, screening for cystic fibrosis mutations, amniotic fluid digestive enzyme activities. RESULTS: The four examples we present-biliary duct atresia, biliary agenesis, gallbladder reveal at birth, and cystic fibrosis-illustrate the difficulties of making both diagnosis and prognosis prenatally when the gallbladder is not visualized. Laboratory assays allowed prenatal management. CONCLUSION: Failure to visualize the gallbladder prenatally may indicate fetal diseases of highly variable prognosis, but may also sometimes be followed by postnatal visualization in a child free of any disease. Prenatal management could help in defining diagnosis and prognosis.

Matthew-Wood syndrome is caused by truncating mutations in the retinol-binding protein receptor gene STRA6.

Retinoic acid (RA) is a potent teratogen in all vertebrates when tight homeostatic controls on its endogenous dose, location, or timing are perturbed during early embryogenesis. STRA6 encodes an integral cell-membrane protein that favors RA uptake from soluble retinol-binding protein; its transcription is directly regulated by RA levels. Molecular analysis of STRA6 was undertaken in two human fetuses from consanguineous families we previously described with Matthew-Wood syndrome in a context of severe microphthalmia, pulmonary agenesis, bilateral diaphragmatic eventration, duodenal stenosis, pancreatic malformations, and intrauterine growth retardation. The fetuses had either a homozygous insertion/deletion in exon 2 or a homozygous insertion in exon 7 predicting a premature stop codon in STRA6 transcripts. Five other fetuses presenting at least one of the two major signs of clinical anophthalmia or pulmonary hypoplasia with at least one of the two associated signs of diaphragmatic closure defect or cardiopathy had no STRA6 mutations. These findings suggest a molecular basis for the prenatal manifestations of Matthew-Wood syndrome and suggest that phenotypic overlap with other associations may be due to genetic heterogeneity of elements common to the RA- and fibroblast growth factor-signaling cascades.

Fetal supraventricular tachycardia: a role for amiodarone as second-line therapy?

OBJECTIVE: The aim of this study was to evaluate the role of amiodarone for the prenatal treatment of hydropic fetuses with supraventricular tachycardia. METHODS: A group of 26 hydropic fetuses with supraventricular tachycardia was studied retrospectively. RESULTS: Twenty-five fetuses received transplacental treatment. The overall prenatal conversion rate was 60%. Nine fetuses were converted to sinus rhythm using either flecainide (n = 7) or amiodarone (n = 2) as first line therapy, whilst digoxin alone or in association with sotalol failed to restore sinus rhythm in all cases. After first-line therapy, supraventricular tachycardia persisted in 10 fetuses. Nine fetuses received amiodarone alone or in association with digoxin as second-line therapy, five of whom were converted to sinus rhythm. Among the 11 live neonates treated by amiodarone in utero, 2 (17%) presented an elevated thyroid stimulating hormone at day 3-4. These two infants received thyroid hormone substitution therapy and had a normal outcome. CONCLUSION: When first-line therapy fails to restore sinus rhythm in hydropic fetuses with supraventricular tachycardia, amiodarone therapy should be considered as it allows a substantial number of fetuses to be converted prenatally.

[Routine sentinel node detection in breast cancer. Experience of the Curie Institute]. / Le ganglion sentinelle en routine dans le cancer du sein: expérience de l'Institut Curie.

Since January 2000, sentinel lymph node detection is routinely performed at the Institut Curie, involving a multidisciplinary team of trained surgeons, nuclear medicine physicians, radiologists and pathologists. During a three-year period, 738 patients undergoing tumorectomy with conservative surgical treatment of the breast were included in the sentinel node procedure consisting of systematic pre-operative tumor biopsies, peritumoral lymph tracer injections at tumor contact (radionuclide/blue dye), primary surgical removal of the first sentinel lymph node, frozen section diagnosis, followed by a standardized pathological analysis, and finally the application of precise criteria to determine whether further surgery is necessary. This article is an evaluation of the sentinel lymph node technique in a specialized Center providing a breakdown of the strong points and weak points of the procedure.