Bone involvement and mineral metabolism in Williams' syndrome.

CONTEXT: The previous studies suggested a possible increased risk of hypercalcaemia and reduced bone mineral density (BMD) in Williams' syndrome (WS). However, an extensive study regarding bone metabolism has never been performed. OBJECTIVE: To investigate bone health in young adults with WS. DESIGN: Cross-sectional study. SETTINGS: Endocrinology and Metabolic Diseases and Medical Genetic Units. PATIENTS: 29 WS young adults and 29 age- and sex-matched controls. MAIN OUTCOME MEASURES: In all subjects, calcium, phosphorus, bone alkaline phosphatase (bALP), parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHVitD), osteocalcin (OC), carboxyterminal cross-linking telopeptide of type I collagen (CTX), 24-h urinary calcium and phosphorus, femoral-neck (FN) and lumbar-spine (LS) BMD and vertebral fractures (VFx) were assessed. In 19 patients, serum fibroblast growth factor-23 (FGF23) levels were measured. RESULTS: WS patients showed lower phosphorus (3.1 ± 0.7 vs 3.8 ± 0.5 mg/dL, p = 0.0001) and TmP/GFR (0.81 ± 0.32 vs 1.06 ± 0.25 mmol/L, p = 0.001), and an increased prevalence (p = 0.005) of hypophosphoremia (34.5 vs 3.4%) and reduced TmP/GFR (37.9 vs 3.4%). Moreover, bALP (26.3 ± 8.5 vs 35.0 ± 8.0 U/L), PTH (24.5 ± 12.6 vs 33.7 ± 10.8 pg/mL), OC (19.4 ± 5.3 vs 24.5 ± 8.7 ng/mL), and FN-BMD (- 0.51 ± 0.32 vs 0.36 ± 0.32) were significantly lower (p < 0.05), while CTX significantly higher (401.2 ± 169.3 vs 322.3 ± 122.4 pg/mL, p < 0.05). Serum and urinary calcium and 25OHVitD levels, LS-BMD and VFx prevalence were comparable. No cases of hypercalcemia and suppressed FGF23 were documented. Patients with low vs normal phosphorus and low vs normal TmP/GFR showed comparable FGF23 levels. FGF23 did not correlate with phosphorus and TmP/GFR values. CONCLUSIONS: Adult WS patients have reduced TmP/GFR, inappropriately normal FGF23 levels and an uncoupled bone turnover with low femoral BMD.

Characterization of multi-locus imprinting disturbances and underlying genetic defects in patients with chromosome 11p15.5 related imprinting disorders.

The identification of multilocus imprinting disturbances (MLID) appears fundamental to uncover molecular pathways underlying imprinting disorders (IDs) and to complete clinical diagnosis of patients. However, MLID genetic associated mechanisms remain largely unknown. To characterize MLID in Beckwith-Wiedemann (BWS) and Silver-Russell (SRS) syndromes, we profiled by MassARRAY the methylation of 12 imprinted differentially methylated regions (iDMRs) in 21 BWS and 7 SRS patients with chromosome 11p15.5 epimutations. MLID was identified in 50% of BWS and 29% of SRS patients as a maternal hypomethylation syndrome. By next-generation sequencing, we searched for putative MLID-causative mutations in genes involved in methylation establishment/maintenance and found two novel missense mutations possibly causative of MLID: one in NLRP2, affecting ADP binding and protein activity, and one in ZFP42, likely leading to loss of DNA binding specificity. Both variants were paternally inherited. In silico protein modelling allowed to define the functional effect of these mutations. We found that MLID is very frequent in BWS/SRS. In addition, since MLID-BWS patients in our cohort show a peculiar pattern of BWS-associated clinical signs, MLID test could be important for a comprehensive clinical assessment. Finally, we highlighted the possible involvement of ZFP42 variants in MLID development and confirmed NLRP2 as causative locus in BWS-MLID.

Phenotype of five cases of prenatally diagnosed campomelic dysplasia harboring novel mutations of the SOX9 gene.

OBJECTIVES: Campomelic dysplasia is a rare congenital skeletal disorder characterized by bowing of the long bones and a variety of other skeletal and extraskeletal defects, many of which can now be identified prenatally using advanced ultrasound equipment. The disorder is caused by mutations in SRY-box 9 (SOX9), a gene that is abundantly expressed in chondrocytes as well as in other tissues. However, the correlation between genotype and phenotype is still unclear. We report five cases of prenatally detected campomelic dysplasia in which the diagnosis was confirmed by molecular analysis. METHODS: Ultrasound examinations were performed between 12 and 32 weeks. Standard fetal biometric measurements were obtained. Fetal sex was determined sonographically and confirmed by chromosomal analysis. Genomic DNA was obtained in four cases before termination of pregnancy from chorionic villi or amniocytes and in one case postnatally from peripheral blood. RESULTS: Skeletal dysplasia, most often limb shortening and bowed femora, was observed in one case in the first trimester, in three cases in the second trimester and in one case, presenting late for antenatal care, in the third trimester. Four of the pregnancies were terminated and one was carried to term. Postmortem/postnatal physical and radiographic examinations confirmed the presence of anomalies characteristic of campomelic dysplasia. A de novo mutation in the SOX9 gene was detected in all four cases that underwent termination. The father of the proband in the case that went to term was a carrier of a somatic mosaic mutation without clinical or radiographic signs of campomelic dysplasia. CONCLUSIONS: It is likely that the integrated expertise of ultrasonographers, obstetricians, pediatricians and clinical geneticists will markedly improve the likelihood of accurate prenatal clinical diagnoses of campomelic dysplasia. This will, in turn, encourage more specific molecular testing and facilitate comprehensive genetic counseling.

[Rare diseases: the model of Ospedale Maggiore Policlinico IRCCS Mangiagalli Regina Elena]. / Malattie rare: il modello della Fondazione Ospedale Mag- giore Policlinico IRCCS Mangiagalli Regina Elena.

The rare diseases are a group of diseases which diagnosis, treatement and prevention is a relevant problem all over the world. They are defined on the basis of their very low incidence also if this definition is not equal all over the world. The article offers a review of the national and regional legislation on rare diseases and it describes a survey carried out in Fondazione Ospedale Maggiore Policlinico IRCCS Mangiagalli Regina Elena, a research and teaching hospital, about the organization of the network of doctors who care for these patients.

Cryptic deletions are a common finding in "balanced" reciprocal and complex chromosome rearrangements: a study of 59 patients.

Using array comparative genome hybridisation (CGH) 41 de novo reciprocal translocations and 18 de novo complex chromosome rearrangements (CCRs) were screened. All cases had been interpreted as "balanced" by conventional cytogenetics. In all, 27 cases of reciprocal translocations were detected in patients with an abnormal phenotype, and after array CGH analysis, 11 were found to be unbalanced. Thus 40% (11 of 27) of patients with a "chromosomal phenotype" and an apparently balanced translocation were in fact unbalanced, and 18% (5 of 27) of the reciprocal translocations were instead complex rearrangements with >3 breakpoints. Fourteen fetuses with de novo, apparently balanced translocations, all but two with normal ultrasound findings, were also analysed and all were found to be normal using array CGH. Thirteen CCRs were detected in patients with abnormal phenotypes, two in women who had experienced repeated spontaneous abortions and three in fetuses. Sixteen patients were found to have unbalanced mutations, with up to 4 deletions. These results suggest that genome-wide array CGH may be advisable in all carriers of "balanced" CCRs. The parental origin of the deletions was investigated in 5 reciprocal translocations and 11 CCRs; all were found to be paternal. Using customized platforms in seven cases of CCRs, the deletion breakpoints were narrowed down to regions of a few hundred base pairs in length. No susceptibility motifs were associated with the imbalances. These results show that the phenotypic abnormalities of apparently balanced de novo CCRs are mainly due to cryptic deletions and that spermatogenesis is more prone to generate multiple chaotic chromosome imbalances and reciprocal translocations than oogenesis.

Nasopharyngeal teratoma and diaphragmatic hernia: a non random association?

We describe a female affected by diaphragmatic hernia and nasopharyngeal teratoma. The case is compared with one already reported and possible diagnoses discussed. These cases appear to represent a new syndrome.

The role of integrated imaging techniques for prenatal prediction of phenotype in two cases of facial anomalies.

OBJECTIVES: Fetal face malformations represent one of the most challenging prenatal diagnoses mainly because of the wide range of morphological features involved. We tested an approach based on a combination of conventional two-dimensional ultrasound with the more recent three-dimensional technique plus magnetic resonance imaging, in order to improve parents' understanding of fetal face anomalies, thereby facilitating parent counselling. METHODS: Two cases of fetal facial anomaly were studied using these combined techniques; one had severe micrognathia and malformation of the ears with preauricular tags, while the other had bilateral dacryocystocele and severe hypertelorism. RESULTS: The images generated by three-dimensional ultrasound enabled the parents to visualize their child immediately and helped them to adjust to the diagnosis of facial defects and its clinical consequences. CONCLUSIONS: An approach based on combined use of different imaging techniques was found useful in both cases.

Prenatal diagnosis of JAK3 deficient SCID.

The JAK3 gene, encoding a tyrosine kinase functionally coupled to cytokine receptors which share the common gamma chain, has been identified as the defective gene for autosomal recessive severe combined immunodeficiency (SCID). Thus, specific mutational diagnosis has become possible. We screened all exons with a combined single strand conformational polymorphism and hetero-duplex formation assay followed by sequence analysis to identify specific mutations in two families. This assay was used on chorionic villus sampling derived DNA in two fetuses from two unrelated families, where we found mutations in both parents. We were able to exclude the mutations in both fetuses by the 12th week of gestation. The described method for first-trimester prenatal diagnosis of autosomal recessive T-B+SCID provides a valid tool to aid in genetic counselling and possibly prenatal therapy in this disease.

Prenatal molecular diagnosis of Wiskott-Aldrich syndrome by direct mutation analysis.

We have performed prenatal diagnosis for Wiskott Aldrich syndrome (WAS) in two unrelated families by direct gene analysis. Using a combined non-radioactive analysis of single-strand conformational polymorphism (SSCP) and heteroduplex formation (HD), followed by automated sequencing, we studied DNA from chorionic villus sampling (CVS), allowing the diagnosis of one affected and one healthy male at the 12th week of gestation.

An unusual fragile X sibship: female compound heterozygote and male with a partially methylated full mutation.

We describe here a fragile X sibship of borderline retarded sister and brother born to carrier parents. The sister is a compound heterozygote (with a full mutation on one X chromosome and a pre-mutation on the other X chromosome). The brother has a partially methylated full mutation. The activation ratio (AR) for the sister's pre-mutation was 0.69 and the percent lack of methylation for the brother's full mutation was 73%. Intellectual and neuropsychological Wechsler Adult Intelligence Scale (W.A.I.S.) achievement tests reported full scale IQ scores of 74 in the sister and 77 in the brother. A significant discrepancy between verbal and performance IQ was found in the sister, indicating that her main impairment was in the cognitive area. The parents of this unusual sibship came from a small village, as did one of the two previously described cases of compound heterozygous females. These rare females raise special issues for genetic counselling in fragile X carrier couples, the frequency of which remains to be defined in different populations.

Prenatal diagnosis of genetic syndromes may be facilitated by serendipitous findings at fetal blood sampling.

Two women without a specific risk had fetuses with multiple malformations diagnosed by ultrasound; extensive biochemical investigations on fetal blood revealed clues which would have allowed the correct diagnosis of a genetic condition: Pallister-Killian syndrome in one with increased fetal LDH, and Smith-Lemli-Opitz type II syndrome in the other with low fetal cholesterolaemia. When compared with chorionic villus sampling and amniocentesis, rapid karyotyping in women with multiple fetal malformations by fetal blood sampling allows the collection of additional data which may lead to the diagnosis of specific genetic syndromes.

Trisomic zygote rescue revealed by DNA polymorphism analysis in confined placental mosaicism.

Uniparental disomy can be caused by different genetic mechanisms such as gamete complementation, chromosome duplication in monosomic zygote, or post-zygotic aneuploidy correction. This last mechanism is well documented in human reproduction and is related to placental mosaicism. In the case of a trisomic zygote which has originated by paternal or maternal non-disjunction at the first or second meiotic cell division, mosaicism will result from chromosome loss and restoration of a 'normalized' diploid fetal karyotype. In order to enrich the literature with new observations on this subject, we studied by DNA polymorphism analysis ten cases of confined placental mosaicism (CPM). The finding in placental DNA of three different alleles at polymorphic loci of chromosomes 13, 16, and 20 demonstrated the trisomic status of the zygote in three cases. On the basis of these results, we believe that systematic DNA polymorphism analysis could give useful additional information to improve knowledge on aneuploidy correction in human reproduction.

The Williams syndrome: an Italian collaborative study.

Williams syndrome (WS) is a multiple congenital anomalies/mental retardation syndrome caused by a microdeletion on the long arm of chromoome 7 including the elastin gene. Possibly it is a contiguous gene syndrome with autosomal dominant transmission. Seventy-seven WS patients from 11 Italian Pediatric-Dysmorphology-Genetics Units were collected by means of a questionnaire designed to draw a comprehensive clinical picture, to define the frequency of different traits and associations thereof, to better understand the clinical evolution, to improve the prognosis and to ameliorate the follow-up. The most important signs for diagnosis, based on their relative frequencies, are: mental retardation with characteristic outgoing behaviour and hoarse voice; facial findings like stellate iris, periorbital fullness and thick lips; congenital heart disease. The frequency of the clinical signs reported in our patients are on the whole concordant with those found in the literature; the only significant differences concern low stature, hallus valgus, hypoplastic nails, joint contractures and ear infections. The multisystemic nature of this syndrome requires a coordinated and integrated approach in order to avoid fragmentary interventions.

[Odontochondrodysplasia]. / L'odontochondrodysplasie.

BACKGROUND: Dentinogenesis imperfecta is exceptionally associated to chondrodysplasia. The aim of this work is to present four cases of such an association. CASE REPORT: These four children (three boys; one girl) suffered from growth retardation, ligamentous hyperlaxity, scoliosis. Main features were present since the first months of life. Dentinogenesis imperfecta was more marked on the first teeth. On X-rays, all patients had short tubular bones, more pronounced at the level of the middle segment of their limbs, with irregular metaphyses. Cone-shaped epiphyses were present on the hands. Iliac wings were square-shaped and vertebral bodies had a posterior wedging. CONCLUSION: These four cases, including two previously published as Goldblatt's syndrome, share the same findings as another case described by this author. We propose the name of odontochondrodysplasia for this apparently unfortuitous association: dentinogenesis imperfecta and chondrodysplasia.

Cardio-facio-cutaneous (CFC) syndrome: report of an adult without mental retardation.

We report on a 25-year-old woman with typical manifestations of the cardio-facio-cutaneous (CFC) syndrome, but without mental retardation. She had valvular and infundibular pulmonic stenosis, brittle and woolly hair with patchy alopecia, scant body hair, dry and hypohydrotic skin, and characteristic facial traits. To our knowledge, this is the first case of CFC syndrome without mental retardation but typical cutaneous findings.