Comparison of CPAP and oxygen therapy for treatment of postoperative hypoxaemia in dogs.

OBJECTIVE: To compare 5 cmH2 O of continuous positive airway pressure with oxygen therapy in dogs recovering from general anaesthesia with low SpO2 values. continuous positive airway pressure is more effective than oxygen therapy in restoring normoxaemia (SpO2 ≥95%). MATERIALS AND METHODS: Prospectively, dogs recovering from anaesthesia, with SpO2 <95% after extubation (T0), were randomised and treated with continuous positive airway pressure (FiO2 0.21) or oxygen (O2 ; FiO2 0.35-0.40) therapy. Dogs were monitored with SpO2 every 15 minutes for 1 hour (T15, T30, T45, T60). Data from normoxaemic dogs (SpO2 >95%) were used as control (CTR). RESULTS: Of the 42 dogs enrolled, 34 completed the study. Eleven dogs were treated with O2 , 10 with continuous positive airway pressure and 13 were CTR. The SpO2 values at T0 were similar in the continuous positive airway pressure and O2 groups and were lower than in the CTR group. At T15, T30, T45 and T60, the SpO2 values in the continuous positive airway pressure group were higher than at T0; these were similar to those of the CTR group at the same time-points. In the O2 group, SpO2 values were significantly higher at T45 and T60 than at T0; 45.5% of dogs became normoxaemic at T45 and the remaining dogs became normoxaemic at T60. The average time to reach normoxaemia in the O2 group (53.1±7.3 minutes) was longer than in the continuous positive airway pressure group (15.0±0.0 minutes). CLINICAL SIGNIFICANCE: In dogs recovering from general anaesthesia with pulmonary gas exchange impairment, normoxaemia is restored more effectively and rapidly by using continuous positive airway pressure than by oxygen therapy.

Characterization of endocrine features and genotype-phenotypes correlations in blepharophimosis-ptosis-epicanthus inversus syndrome type 1.

OBJECTIVE: Blepharophimosis syndrome (BPES) is an autosomal dominant genetic condition resulting from heterozygous mutations in the FOXL2 gene and clinically characterized by an eyelid malformation associated (type I) or not (type II) with premature ovarian failure. The distinction between the two forms is critical for female patients, as it may allow to predict fertility and to plan an appropriate therapy. Identifying an underlying causative mutation is not always predictive of the clinical type of BPES since genotype-phenotype correlations are not yet fully delineated. Here, we describe the clinical and hormonal phenotypes of three female patients with BPES type 1 from two novel families, correlate their phenotypes with identified mutations, and investigate the effects of hormone replacement therapy (HRT). METHODS: Clinical, biochemical, and genetic evaluation were undertaken in all the patients and genotype-phenotype correlation was analyzed. The effects of substitutive hormonal therapy on secondary sexual characteristics development and induction of menarche were evaluated. RESULTS: All patients presented with primary amenorrhea or other signs of ovarian dysfunction. Two distinct mutations, a missense p.H104R change and an in-frame p.A222_A231dup10 duplication in the FOXL2 gene were identified. Observed phenotypes were not in accordance with the prediction based on the current genotype-phenotype correlations. HRT significantly improved secondary sexual characteristics development, as well as the induction of menarche. CONCLUSIONS: This study highlights the importance of early recognition of BPES and emphasizes the need of personalized therapy and follow-up in female patients carrying distinct FOXL2 mutations.

Two 48,XXYY patients: clinical, cytogenetic and molecular aspects.

Two 48,XXYY males, a young and an adult patient, have been clinically and molecularly analysed. Clinical findings seem less severe in the young patient. This clinical difference could be mainly due to the age of the younger patient or, alternatively, the different pattern of X-inactivation observed in the two patients could play a role in the degree of the clinical manifestations.

Identification of LMX1B gene point mutations in italian patients affected with Nail-Patella syndrome.

Nail-Patella syndrome, or osteo-onychodysplasia, is an autosomal dominant disorder characterized by nail dysplasia, absent or hypoplastic patellae, iliac horns and nephropathy. Previous studies have demonstrated linkage of the Nail-Patella locus with polymorphic markers on human chromosome 9q34. Recently, point mutations in the LMX1B gene have been identified in Nail-Patella patients and in families with recurrence of Nail-Patella syndrome and open-angle glaucoma. We describe here the identification of additional point mutations in the LMX1B gene in a set of Italian patients affected with Nail-Patella syndrome: two deletions of 1 and 2 bp causing a frameshift in two sporadic patients and nonsense mutations in two familial and one sporadic cases have been identified. All the mutations affect the homeodomain of the LMX1B protein and could cause the Nail-Patella syndrome through a loss of function as well as a dominant negative effect. Haplotype analysis in the two familial cases carrying the same stop codon mutation suggests the presence of a founder effect. Finally, analysis of cDNA clones obtained from human fetal kidney has revealed the existence of two different transcripts of LMX1B gene likely due to an alternative splicing.

Linkage analysis in two large Italian pedigrees affected with nail patella syndrome.

Nail patella syndrome (NPS) or osteo-onychodysplasia, is an autosomal dominant disorder characterised by nail dysplasia, absent or hypoplastic patellae, iliac horns and nephropathy. Previous studies have demonstrated linkage of the nail patella locus to the ABO and adenylate kinase loci on human chromosome 9q34. Recently, informative recombination events placed the NPS locus within a 1-2 cM interval within D9S60 and the AK1 gene. We describe here linkage analysis performed in two large Italian pedigrees with 10 and 11 members affected, respectively. A set of highly informative markers have been analysed and the allele segregation in the two families confirmed the linkage to chromosome 9. The presence of three recombination events allows definition of the critical region with a centrometric boundary between markers D9S1881 and D9S1840 and a telomeric boundary between markers D9S315 and D9S290.

Detection of dystrophin deletion carriers using FISH analysis.

The detection of carrier status in female relatives of Duchenne/Becker muscular dystrophy patients is not always possible and this poses a problem in genetic counseling. We have developed a simple method that can be used in families in which affected males are characterized by the presence of a deletion within the dystrophin gene. PCR fragments, corresponding to the deleted regions are used as fluorescent probes for hybridization of peripheral lymphocytes nuclei of female relatives. The results obtained clearly demonstrate the feasibility of this method for detecting female DMD/BMD carriers.

A YAC contig spanning the blepharophimosis-ptosis-epicanthus inversus syndrome and propionic acidemia loci.

Blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) is an autosomal dominant condition consisting of congenital dysplasia of the eyelids with a reduced horizontal diameter of the palpebral fissures, droopy eyelids and epicanthus inversus. Two clinical entities have been described: type I and type II. The former is distinguished by female infertility, whereas the latter presents without other symptoms. Both type I and type II were recently mapped on the long arm of chromosome 3 (3q22-q23), suggesting a common gene may be affected. The centromeric and the telomeric limits of this region are well defined between loci D3S1316 and D3S1615, which reside approximately 5 cM apart. Here, we present the construction of a YAC contig spanning the entire BPES locus using 17 polymorphic markers, 2 STS and 28 ESTs. This region of approximately 5 Mb was covered by 31 YACs, and was supported by detailed FISH analysis. In addition, we have precisely mapped the propionyl-CoA carboxylase beta polypeptide (PCCB), the gene mutated in propionic acidemia, within this contig. Apart from providing a framework for the identification of the BPES gene, this contig will also be useful for the future identification of defects and genes mapped to this region, and for developing template resources for genomic sequencing.

Two newborns with chromosome 4 imbalances: deletion 4q33-->q35 and ring r(4)(pterq35.2-qter).

Two patients are reported who presented with 4q deletion and r(4), respectively. Cytogenetic and FISH analysis defined the breakpoints respectively at bands 4q33-->q35 proximal to the telomere, and 4pter and 4q35.2 qter. Moreover in both cases rearranged chromosomes maintained telomeric sequences. The first patient showed some clinical features of deletion 4q and a pointed 5th finger, a characteristic finding in deletion 4q31-->qter. The second patient had mild dysmorphism associated with growth retardation.

Linkage analysis of Fanconi anaemia in Italy and mapping of the complementation group A gene.

Fanconi anaemia (FA) is an autosomal recessive disease characterised by genetic heterogeneity, with at least five complementation groups (FA-A to FA-E). The FAC gene has been cloned and localised to 9q22.3. The most frequent defective gene, FAA, was recently mapped to chromosome 16q24.3, in a region of 10 cM between D16S498 and the telomere. Eleven FA-A and 16 unclassified Italian families were analysed by microsatellite markers. To define the localisation of the FAA locus further, microsatellites were analysed at 16q24. All the families were consistent with linkage, the highest lod score being observed with D16S1320. Evidence for common haplotypes was obtained in two genetic isolates from the Brenta basin and the Naples region. Autozygosity mapping and haplotype analysis suggest that the FAA locus is distal to D16S305.

Screening of neurofibromatosis type 1 gene: identification of a large deletion and of an intronic variant.

Neurofibromatosis type 1 of von Recklinghausen is a common autosomal dominant disorder, characterized by peripheral neurofibromas, café-au-lait spots and Lisch nodules of the iris. The high mutation rate at the neurofibromatosis type 1 locus results in a wide range of molecular abnormalities. We have screened seven different exons of the neurofibromatosis type 1 gene, including those codifying for the GAP-related domain, using the RNA-Single Strand Conformation Polymorphism (RNA-SSCP) method in a series of 59 neurofibromatosis type 1 patients. We have also analyzed four intragenic repeats and one RFLP to detect hemizygosity and evaluate informativeness in at-risk families. One deletion and a new intronic normal variant have been detected. Thus the majority of Neurofibromatosis type 1 chromosomes have not been characterized, confirming difficulty in providing proper genetic counselling in neurofibromatosis type 1 families, even following extensive DNA analysis.

Cytogenetic and molecular analysis of trisomy 9. Case report and review.

A newborn infant with the full manifestations of trisomy 9 syndrome is reported. Cytogenetic analysis reveled an homogeneous aneuploidy. Molecular studies using polymorphic microsatellites of chromosome 9 showed that non disjunction occurred at maternal meiosis II.