Binder phenotype in mothers affected with autoimmune disorders

OBJECTIVE

To report four foetal cases of the Binder phenotype associated with maternal autoimmune disorders.

PATIENTS AND METHODS

In three mothers with autoimmune diseases, 2D and 3D ultrasonographic measurements were made on four foetuses with the Binder profile, and were compared with postnatal phenotypes.

RESULTS

The Binder phenotype can be detected in early pregnancy (14.5 WG). All foetuses had verticalized nasal bones and midfacial hypoplasia. Punctuate calcifications were found in almost all the cases. No specific maternal auto-antibody has been associated with foetal Binder phenotype.

CONCLUSION

Since the Binder phenotype can be diagnosed at ultrasound examination during pregnancy, it is important to establish the underlying cause so as to assess the foetal prognosis. This study stresses the importance of systematic checks for maternal autoimmune disease in cases of prenatally diagnosed Binder phenotypes.

Binder phenotype: clinical and etiological heterogeneity of the so-called Binder maxillonasal dysplasia in prenatally diagnosed cases, and review of the literature

OBJECTIVE

Prenatal Binder profile is a well known clinical phenotype, defined by a flat profile without nasal eminence, contrasting with nasal bones of normal length. Binder profile results of a hypoplasia of the nasal pyramid (sometimes referred to as maxillonasal dysplasia). We report 8 fetuses prenatally diagnosed as Binder phenotype, and discuss their postnatal diagnoses.

METHODS

Ultrasonographic detailed measurements in 2D and 3D were done on the 8 fetuses with Binder profile, and were compared with postnatal phenotype.

RESULTS

All fetuses have an association of verticalized nasal bones, abnormal convexity of the maxilla, and some degree of chondrodysplasia punctata. The final diagnoses included fetal warfarin syndrome (one patient), infantile sialic acid storage (one patient), probable Keutel syndrome (one patient), and five unclassifiable types of chondrodysplasia punctata.

CONCLUSION

This series demonstrates the heterogeneity of prenatally diagnosed Binder phenotype, and the presence of chondrodysplasia punctata in all cases. An anomaly of vitamin K metabolism, possibly due to environmental factors, is suspected in these mild chondrodysplasia punctata. We recommend considering early prophylactic vitamin K supplementation in every suspected acquired vitamin K deficiency including incoercible vomiting of the pregnancy.

2q23.1 microdeletion identified by array comparative genomic hybridisation: an emerging phenotype with Angelman-like features?

BACKGROUND

Genome-wide screening of patients with mental retardation using array comparative genomic hybridisation (CGH) has identified several novel imbalances. With this genotype-first approach, the 2q22.3q23.3 deletion was recently described as a novel microdeletion syndrome. The authors report two unrelated patients with a de novo interstitial deletion mapping in this genomic region and presenting similar "pseudo-Angelman" phenotypes, including severe psychomotor retardation, speech impairment, epilepsy, microcephaly, ataxia, and behavioural disabilities.

METHODS

The microdeletions were identified by array CGH using oligonucleotide and bacterial artificial chromosome (BAC) arrays, and further confirmed by fluorescence in situ hybridisation (FISH) and semi-quantitative polymerase chain reaction (PCR).

RESULTS

The boundaries and sizes of the deletions in the two patients were different but an overlapping region of about 250 kb was defined, which mapped to 2q23.1 and included two genes: MBD5 and EPC2. The SIP1 gene associated with the Mowat-Wilson syndrome was not included in the deleted genomic region.

DISCUSSION

Haploinsufficiency of one of the deleted genes (MBD5 or EPC2) could be responsible for the common clinical features observed in the 2q23.1 microdeletion syndrome, and this hypothesis needs further investigation.

De novo Subtelomeric Deletion Additional to an Inherited Apparently Balanced Reciprocal Translocation

OBJECTIVE

We describe the analysis of an apparently balanced inherited reciprocal translocation in a fetus presenting with multiple congenital abnormalities, characterize the structural chromosome rearrangement, and report an unexpected additional imbalance to the inherited rearrangement.

METHODS

DNA microarray was used to screen for genomic imbalance in subtelomeric and interstitial critical regions. High-resolution comparative genomic hybridization was used to screen for genomic imbalance at a genome-wide level. Fluorescence in situ hybridization using whole-chromosome painting and specific probes was used to characterize the inherited translocation, and the size of the de novoadditional deletion.

RESULTS

An unexpected additional deletion was found in 7qter on derivative 10 of the inherited maternal reciprocal translocation t(7;10)(q11.23; p14).

CONCLUSIONS

We show the usefulness of genome-wide and specific molecular cytogenetic techniques to explore apparently balanced rearrangements.

Intrafamilial segregation analysis of the p.E148Q MEFV allele in familial Mediterranean fever

BACKGROUND

Familial Mediterranean fever (FMF) is the most frequent of the recurrent inherited fevers. This autosomal recessive disorder is characterised by periodic episodes of fever and serositis that commonly affect the people of Arab, Armenian, Sephardic Jewish and Turkish origin. Most of the described MEFV gene anomalies responsible for the disease are missense mutations. In the absence of any functional test, epidemiological studies or pedigree analyses are the only means of proving the deleterious character of these sequence variations. Evidence was provided by our recent study using a population-based approach, that the p.E148Q allele is probably a benign polymorphism and not a disease-causing mutation. Its implication in FMF remains, however, controversial.

OBJECTIVE

To evaluate the segregation of the p.E148Q MEFV allele with FMF disease by using pedigree analysis.

PARTICIPANTS

21 patients and 48 unaffected relatives belonging to 18 independent families with FMF.

RESULTS

Segregation analysis of the p.E148Q allele was compatible with a Mendelian autosomal recessive transmission of the disease phenotype in only three families. In 15 of 18 families, segregation was partly or completely defective. The p.E148Q allele was not transmitted to 14 of 19 (74%) affected children.

CONCLUSIONS

No evidence of preferential transmission of p.E148Q from heterozygous parents to their affected offspring was observed. MEFV is not associated with the clinical manifestations of several patients carrying this variant. Considering p.E148Q to be a benign polymorphism should reduce the possibility of false-positive diagnoses, while highlighting genetic heterogeneity in FMF.

Prenatal forehead edema in 4p- deletion: the ‘Greek warrior helmet’ profile revisited

OBJECTIVES

Deletion of short arm of chromosome 4 is difficult to ascertain prenatally, and can be missed.

METHODS

A prenatal suspicion of 4p- syndrome was thoroughly investigated by using two-dimensional and three-dimensional sonography, with a description of the fetal face dysmorphological pattern. The cytogenetic confirmation, obtained by karyotype and FISH technique, allowed a precise description of the prenatal abnormalities. Post-termination tridimensional helicoidal scanner of the fetal face was performed.

RESULTS

The main anomaly discovered using two-dimensional sonography was the presence of a strikingly thick prefrontal edema (8 mm, twice the normal values, at 22 weeks: 3.81 +/- 0.62 mm). Three-dimensional sonography showed the classical postnatal profile, with the phenotypic aspect of a 'Greek warrior helmet'. Nasal bones were normal in size and placement, confirmed by helicoidal scanner.

CONCLUSION

Prenatal diagnosis of 4p deletion syndrome can be difficult, and it is the presence of prefrontal edema, associated with more subtle facial anomalies (short philtrum, microretrognathia) which should trigger cytogenetic investigation for 4p- deletion, even with only borderline growth retardation.

Mosaic trisomy 15 and hemihypertrophy

We report a case of mosaic trisomy 15 with mental retardation, facial dysmorphism, and hemihypertrophy, but no manifestations of Prader-Willi or Angelman syndromes. Mosaic trisomy 15 (11%) was discovered at the amniocentesis. Uniparental disomy for chromosome 15 was excluded by molecular analysis. Post-natal blood karyotype and examination were normal. Mosaic was confirmed on skin fibroblasts, placenta and cord. Evolution was marked by progressive right hemi-hypertrophy, and developmental delay. Our case is the first patient reported with hemihypertrophy associated with mosaic trisomy 15. The relevant literature is reviewed.

Genotype determination at the survival motor neuron locus in a normal population and SMA carriers using competitive PCR and primer extension

Precise quantitation of SMN1 copy number is of great interest in many clinical applications such as direct detection of SMA carriers or detection of an SMA-affected patient with a hemizygous deletion of the SMN1 gene. We describe a method that combines two independent nonradioactive PCR assays: determination of the relative ratio of the SMN1 and SMN2 genes using a primer extension assay and of the total SMN copy number using competitive PCR. Consistency of the results of two independent approaches ensures the reliability of the deduced genotype and thus avoids false interpretation of borderline results that can occur in quantitative assays. In all, 135 subjects were tested, including 91 normal controls and 44 SMA-affected children or SMA carriers. Two main genotypes were observed in controls: 2T/2C (45%) and 2T/1C (32%). A wide variability at the SMN locus is observed with nine different genotypes and up to six SMN genes. SMA carriers showed three frequent genotypes, 1T/2C (50%), 1T/3C (29%), and 1T/1C (18%). Normal chromosomes with two SMN1 genes per chromosome are not infrequent and thus, about 3% of SMA carriers are not detected using SMN1 copy number quantitation. Finally, as this method does not detect point mutations (4% of SMN1 gene mutations), reliability ranges from 93% to 100% depending on data available from the propositus.