Elastins from patients with Williams-Beuren syndrome and healthy individuals differ on the molecular level.

Williams-Beuren syndrome (WBS) is a congenital disorder, which involves the heterozygous deletion of the elastin gene and other genes on chromosome 7. Clinical symptoms that are associated with hemizygosity of the essential extracellular matrix protein elastin include premature aging of the skin and supravalvular aortic stenosis. However, only little is known about the molecular basis of structural abnormalities in the connective tissue of WBS patients. Therefore, for the first time this study aimed to systematically characterize and compare the structure and amount of elastin present in skin and aortic tissue from WBS patients and healthy individuals. Elastin fibers were isolated from tissue biopsies, and it was found that skin of WBS patients contains significantly less elastin compared to skin of healthy individuals. Scanning electron microscopy and mass spectrometric measurements combined with bioinformatics data analysis were used to investigate the molecular-level structure of elastin. Scanning electron microscopy revealed clear differences between WBS and healthy elastin. With respect to the molecular-level structure, it was found that the proline hydroxylation degree differed between WBS and healthy elastin, while the tropoelastin isoform appeared to be the same. In terms of cross-linking, no differences in the content of the tetrafunctional cross-links desmosine and isodesmosine were found between WBS and healthy elastin. However, principal component analysis revealed differences between enzymatic digests of elastin from healthy probands and WBS patients, which indicates differing susceptibility toward enzymatic cleavage. Overall, the study contributes to a better understanding of the correlation between genotypic and elastin-related phenotypic features of WBS patients. © 2016 Wiley Periodicals, Inc.

Treatment of central precocious puberty and early puberty with GnRH analog in girls with Williams-Beuren syndrome.

OBJECTIVE: Little has been published on treatment of precocious puberty in girls with Williams-Beuren syndrome (WBS), a condition occurring frequently in this group. We analyzed our own data on growth/age at menarche of now adult female patients with WBS being diagnosed with central precocious puberty or early puberty. Data of patients treated with gonadotropin-releasing hormone (GnRH) analog (n=13) were compared with those not treated (control group, n=11). PATIENTS: Longitudinal data on the somatic development of 24 now adult female patients were analyzed. RESULTS: Medium final height was 157.2±6.5 cm compared to 151.4±5.6 cm in the control group. No significant difference could be found in the discrepancy of genetic target height and final height. Prepubertally girls were normal weight in both groups; in adulthood the majority of patients were overweight/obese. Menarche commenced 11 months after cessation of therapy. CONCLUSION: As already known from other studies, hormonal suppression via GnRH analog was well tolerated.

No significantly increased frequency of the inversion polymorphism at the WBS-critical region 7q11.23 in German parents of patients with Williams-Beuren syndrome as compared to a population control.

BACKGROUND: Typical Williams-Beuren syndrome (WBS) is commonly caused by a ~1.5 Mb - ~1.8 Mb heterozygous deletion of contiguous genes at chromosome region 7q11.23. The majority of WBS cases occurs sporadically but few familial cases of autosomal dominant inheritance have been reported. Recent data demonstrated the existence of the paracentric inversion polymorphism at the WBS critical region in 7q11.23 in some of the progenitors transmitting the chromosome which shows the deletion in the affected child. In parents having a child affected by WBS the prevalence of such a structural variant has been reported to be much higher (~25- ~30%) than in the general population (~1- ~6%). However, in these previously reported studies only a limited number of randomly selected patients and non transmitting parents of WBS patients were used as controls, but without specification of any clinical data. Therefore we have undertaken a German population-based molecular cytogenetic investigation. We evaluated the incidence of the paracentric inversion polymorphism at 7q11.23 analyzing interphase nuclei of lymphocytes using a three color fluorescence in situ hybridization (FISH) probe. RESULTS: FISH analysis was carried out on couples with a child affected by WBS as compared to a population sample composed of different normal individuals: Control group I: couples with two healthy children, control group II: couples with fertility problems, planning ICSI and control group III: couples with two healthy children and one child with a chromosome aberration, not involving region 7q11.23. The three color FISH assay showed that the frequency of the paracentric inversion polymorphism at 7q11.23 in couples with a child affected by WBS was 20.8% (5 out of 24 pairs) as compared to 8.3% (2 out of 24 pairs, control group I), 25% (4 out of 16 pairs, control group II) and 9.1% (1 out of 11 pairs, control group III), respectively (total 7 out of 51 pairs, 13.8%). The frequencies differed between the groups, but this was statistically not significant (p > 0.05, Fisher's test). CONCLUSION: Our results do not support the hypothesis that the paracentric inversion polymorphism at 7q11.23 is a major predisposing factor for the WBS deletion.

Risk of sudden death in the Williams-Beuren syndrome.

Williams-Beuren syndrome (WBS) is a genetic disorder characterized by a distinctive facial gestalt, mental retardation, mild growth deficiency, and cardiovascular disease. The occurrence of sudden death in the WBS is known from several case reports, but information about the risk of sudden death as derived from the data of a large cohort of patients is lacking. We analyzed the data of 293 WBS patients who had been treated for 43 years at the same two institutions. We thus collected 5,190 patient years without loss to follow-up. During this period ten patients died. Five of them died from: reticulosarcoma (1), after accident (1), heart failure (1), following heart surgery (2). Of the remaining five patients, four died suddenly and one died of unknown cause suggestive of sudden cardiac death. Thus, the incidence of sudden death in our WBS cohort amounts to 1/1,000 patient years. This risk of sudden death is comparable to that following surgery for congenital heart disease, and is 25-100-fold higher compared to the age-matched normal population.

Central precocious puberty in girls with Williams syndrome.

We report an estimated prevalence of precocious puberty of 1 in 5 to 6 girls with Williams syndrome (18.3%). Mean menarcheal age of 86 girls with Williams syndrome was 11.5 +/- 1.7 (+/-SD) years. Distribution of menarcheal age was significantly different from that in normal girls (12.9 +/- 1.1 years; n = 759).