Kenny-Caffey syndrome (KCS) and the similar but more severe osteocraniostenosis (OCS) are genetic conditions characterized by impaired skeletal development with small and dense bones, short stature, and primary hypoparathyroidism with hypocalcemia. We studied five individuals with KCS and five with OCS and found that all of them had heterozygous mutations in FAM111A. One mutation was identified in four unrelated individuals with KCS, and another one was identified in two unrelated individuals with OCS; all occurred de novo. Thus, OCS and KCS are allelic disorders of different severity. FAM111A codes for a 611 amino acid protein with homology to trypsin-like peptidases. Although FAM111A has been found to bind to the large T-antigen of SV40 and restrict viral replication, its native function is unknown. Molecular modeling of FAM111A shows that residues affected by KCS and OCS mutations do not map close to the active site but are clustered on a segment of the protein and are at, or close to, its outer surface, suggesting that the pathogenesis involves the interaction with as yet unidentified partner proteins rather than impaired catalysis. FAM111A appears to be crucial to a pathway that governs parathyroid hormone production, calcium homeostasis, and skeletal development and growth.

Tricho-rhino-phalangeal syndrome (TRPS) is

Stickler syndrome is an autosomal dominant connective tissue disorder caused by mutations in different collagen genes. The aim of our study was to define more precisely the phenotype and genotype of Stickler syndrome type 1 by investigating a large series of patients with a heterozygous mutation in COL2A1. In 188 probands with the clinical diagnosis of Stickler syndrome, the COL2A1 gene was analyzed by either a mutation scanning technique or bidirectional fluorescent DNA sequencing. The effect of splice site alterations was investigated by analyzing mRNA. Multiplex ligation-dependent amplification analysis was used for the detection of intragenic deletions. We identified 77 different COL2A1 mutations in 100 affected individuals. Analysis of the splice site mutations showed unusual RNA isoforms, most of which contained a premature stop codon. Vitreous anomalies and retinal detachments were found more frequently in patients with a COL2A1 mutation compared with the mutation-negative group (Po0.01). Overall, 20 of 23 sporadic patients with a COL2A1 mutation had either a cleft palate or retinal detachment with vitreous anomalies. The presence of vitreous anomalies, retinal tears or detachments, cleft palate and a positive family history were shown to be good indicators for a COL2A1 defect. In conclusion, we confirm that Stickler syndrome type 1 is predominantly caused by loss-of-function mutations in the COL2A1 gene as 490% of the mutations were predicted to result in nonsense-mediated decay. On the basis of binary regression analysis, we developed a scoring system that may be useful when evaluating patients with Stickler syndrome.

Pitt-Hopkins syndrome (PTHS) is characterized by severe intellectual disability, typical facial gestalt and additional features, such as breathing anomalies. Following the discovery of the causative haploinsufficiency of transcription factor 4 (TCF4), about 60 patients have been reported. We looked for TCF4 mutations in 63 patients with a suspected PTHS. Haploinsufficiency of TCF4 was identified in 14 patients, as a consequence of large 18q21.2 chromosome deletions involving TCF4 (2 patients), gene mutations (11 patients) and a t(14q;18q) balanced translocation disrupting TCF4 (one patient). By evaluating the clinical features of these patients, along with literature data, we noticed that, in addition to the typical facial gestalt, the PTHS phenotype results from the various combinations of the following characteristics: intellectual disability with severe speech impairment, normal growth parameters at birth, postnatal microcephaly, breathing anomalies, motor incoordination, ocular anomalies, constipation, seizures, typical behavior and subtle brain abnormalities. Although PTHS is currently considered to be involved in differential diagnosis with Angelman and Rett syndromes, we found that combining the facial characteristics with a detailed analysis of both the physical and the neurological phenotype, made molecular testing for PTHS the first choice. Based on striking clinical criteria, a diagnosis of PTHS was made clinically in two patients who had normal TCF4. This report deals with the first series of PTHS patients of Italian origin.

Rubinstein-Taybi syndrome (RSTS) is a rare congenital neurodevelopmental disorder characterized by postnatal growth deficiency, skeletal abnormalities, dysmorphic features and cognitive deficit. Mutations in two genes, CREBBP and EP300, encoding two homologous transcriptional co-activators, have been identified in ˜55% and ˜3-5% of affected individuals, respectively. To date, only eight EP300-mutated RSTS patients have been described and 12 additional mutations are reported in the database LOVD. In this study, EP300 analysis was performed on 33 CREBBP-negative RSTS patients leading to the identification of six unreported germline EP300 alterations comprising one deletion and five point mutations. All six patients showed a convincing, albeit mild, RSTS phenotype with minor skeletal anomalies, slight cognitive impairment and few major malformations. Beyond the expansion of the RSTS-EP300-mutated cohort, this study indicates that EP300-related RSTS cases occur more frequently than previously thought (˜8% vs 3-5%); furthermore, the characterization of novel EP300 mutations in RSTS patients will enhance the clinical practice and genotype-phenotype correlations.

The study has provided epidemiological data for public health surveillance of congenital heart defects in the Emilia-Romagna region. The creation of a system for the nationwide recording of congenital heart defects designed with regard to the sources of ascertainment, the diagnostic criteria, and the system of classification is emphasised.

The genetic basis of Rubinstein-Taybi syndrome (RSTS), a rare, sporadic, clinically heterogeneous disorder characterized by cognitive impairment and a wide spectrum of multiple congenital anomalies, is primarily due to private mutations in CREBBP (approximately 55% of cases) or EP300 (approximately 8% of cases). Herein, we report the clinical and the genetic data taken from a cohort of 46 RSTS patients, all carriers of CREBBP point mutations. Molecular analysis revealed 45 different gene alterations including 31 inactivating (21 frameshift and 10 nonsense), 10 missense and 4 splicing mutations. Bioinformatic tools and transcript analyses were used to predict the functional effects of missense and splicing alterations. Of the 45 mutations, 42 are unreported and 3 were described previously. Recurrent mutations maybe a key tool in addressing genotype-phenotype correlations in patients sharing the same defects (at the genomic or transcript level) and specific clinical signs, demonstrated here in two cases. The clinical data of our cohort evidenced frequent signs such as arched eyebrows, epicanthus, synophrys and/or frontal hypertrichosis and broad phalanges that, previously overlooked in RSTS diagnosis, now could be considered. Some suggested correlations between organ-specific anomalies and affected CREB-binding protein domains broaden the RSTS clinical spectrum and perhaps will enhance patient follow-up and clinical care.

The parent of origin-dependent expression of the IGF2 and H19 genes is controlled by the imprinting centre 1 (IC1) consisting in a methylation-sensitive chromatin insulator. Deletions removing part of IC1 have been found in patients affected by the overgrowth- and tumour-associated Beckwith-Wiedemann syndrome (BWS). These mutations result in the hypermethylation of the remaining IC1 region, loss of IGF2/H19 imprinting and fully penetrant BWS phenotype when maternally transmitted. We now report that 12 additional cases with IC1 hypermethylation have a similar clinical phenotype but showed neither a detectable deletion nor other mutation in the local vicinity. Likewise, no IC1 deletion was detected in 40 sporadic non-syndromic Wilms' tumours. A detailed analysis of the BWS patients showed that the hypermethylation variably affected the IC1 region and was generally mosaic. We observed that all these cases were sporadic and in at least two families affected and unaffected members shared the same maternal IC1 allele but not the abnormal maternal chromosome epigenotype. Furthermore, the chromosome with the imprinting defect derived from either the maternal grandfather or maternal grandmother. Overall, these results indicate that methylation-imprinting defects at the IGF2-H19 locus can result from inherited mutations of the IC and have high recurrence risk or arise independently from the sequence context and generally not transmitted to the progeny. Despite these differences, the epigenetic abnormalities are usually present in the patients in the mosaic form and probably acquired by post-zygotic de novo methylation. Distinguishing between these two groups of cases is important for genetic counselling.