Further delineation of an entity caused by CREBBP and EP300 mutations but not resembling Rubinstein-Taybi syndrome.

In 2016, we described that missense variants in parts of exons 30 and 31 of CREBBP can cause a phenotype that differs from Rubinstein-Taybi syndrome (RSTS). Here we report on another 11 patients with variants in this region of CREBBP (between bp 5,128 and 5,614) and two with variants in the homologous region of EP300. None of the patients show characteristics typical for RSTS. The variants were detected by exome sequencing using a panel for intellectual disability in all but one individual, in whom Sanger sequencing was performed upon clinical recognition of the entity. The main characteristics of the patients are developmental delay (90%), autistic behavior (65%), short stature (42%), and microcephaly (43%). Medical problems include feeding problems (75%), vision (50%), and hearing (54%) impairments, recurrent upper airway infections (42%), and epilepsy (21%). Major malformations are less common except for cryptorchidism (46% of males), and cerebral anomalies (70%). Individuals with variants between bp 5,595 and 5,614 of CREBBP show a specific phenotype (ptosis, telecanthi, short and upslanted palpebral fissures, depressed nasal ridge, short nose, anteverted nares, short columella, and long philtrum). 3D face shape demonstrated resemblance to individuals with a duplication of 16p13.3 (the region that includes CREBBP), possibly indicating a gain of function. The other affected individuals show a less specific phenotype. We conclude that there is now more firm evidence that variants in these specific regions of CREBBP and EP300 result in a phenotype that differs from RSTS, and that this phenotype may be heterogeneous.

Primary immunodeficiency diseases: Genomic approaches delineate heterogeneous Mendelian disorders.

BACKGROUND: Primary immunodeficiency diseases (PIDDs) are clinically and genetically heterogeneous disorders thus far associated with mutations in more than 300 genes. The clinical phenotypes derived from distinct genotypes can overlap. Genetic etiology can be a prognostic indicator of disease severity and can influence treatment decisions. OBJECTIVE: We sought to investigate the ability of whole-exome screening methods to detect disease-causing variants in patients with PIDDs. METHODS: Patients with PIDDs from 278 families from 22 countries were investigated by using whole-exome sequencing. Computational copy number variant (CNV) prediction pipelines and an exome-tiling chromosomal microarray were also applied to identify intragenic CNVs. Analytic approaches initially focused on 475 known or candidate PIDD genes but were nonexclusive and further tailored based on clinical data, family history, and immunophenotyping. RESULTS: A likely molecular diagnosis was achieved in 110 (40%) unrelated probands. Clinical diagnosis was revised in about half (60/110) and management was directly altered in nearly a quarter (26/110) of families based on molecular findings. Twelve PIDD-causing CNVs were detected, including 7 smaller than 30 Kb that would not have been detected with conventional diagnostic CNV arrays. CONCLUSION: This high-throughput genomic approach enabled detection of disease-related variants in unexpected genes; permitted detection of low-grade constitutional, somatic, and revertant mosaicism; and provided evidence of a mutational burden in mixed PIDD immunophenotypes.

Epidemiology of craniosynostosis in Norway.

OBJECTIVE: The authors present population-based epidemiological data for craniosynostosis regarding incidence, age at diagnosis, sex differences, and frequency of syndromic and familial cases. METHODS: The prospective registry of the Norwegian National Unit for Craniofacial Surgery was used to retrieve data on all individuals with craniosynostosis treated between 2003 and 2017. The cohort was divided into three 5-year groups based on year of birth: 2003-2007, 2008-2012, and 2013-2017. RESULTS: The authors identified 386 individuals with craniosynostosis. Of these, 328 (85%) consented to be registered with further information. The incidence increased significantly during the study period and was 5.5 per 10,000 live births (1/1800) in the last 5-year period. The increase was seen almost exclusively in the nonsyndromic group. Syndromic craniosynostosis accounted for 27% of the cases, and the incidence remained stable throughout the three 5-year periods. Both syndromic and nonsyndromic craniosynostosis were highly suture specific. There was a male preponderance (male/female ratio 2:1), and males accounted for 75% of the individuals with midline synostosis. Overall, 9.5% were index individuals in families with more than one affected member; of these, 73% were nonsyndromic cases. CONCLUSIONS: The incidence of craniosynostosis increased during the study period, and the observed incidence is among the highest reported. The authors attribute this to increasing awareness among healthcare professionals. The number of syndromic cases was high, likely due to a broader definition compared to the majority of earlier reports. The study revealed a high number of familial cases in both syndromic and nonsyndromic craniosynostosis, thus highlighting the importance of genetics as an underlying cause of craniosynostosis.

Abnormally wide eustachian tubes involving the sphenoid bone: A collection.

OBJECTIVES: To present nine patients with an abnormal widened bony Eustachian tube running anteriorly in the skull base through the sphenoid bone. METHODS: Patients with a particular anomaly in the bony Eustachian tube incidentally found on CT examinations were registered consecutively over a period of four years. RESULTS: Nine patients had the anomaly, eight unilaterally and one bilaterally. All our patients had additional anomalies involving the outer, middle, and/or inner ear. CONCLUSION: The consequences of this anomaly remain unknown, but the presence of the widened, bony ET should increase the awareness for complex temporal bone deformities and vice versa. LEVEL OF EVIDENCE: 4.

Renal Amyloidosis Associated With 5 Novel Variants in the Fibrinogen A Alpha Chain Protein.

INTRODUCTION: Fibrinogen A alpha chain amyloidosis is an autosomal dominant disease associated with mutations in the fibrinogen A alpha chain (FGA) gene, and it is the most common cause of hereditary renal amyloidosis in the UK. Patients typically present with kidney impairment and progress to end-stage renal disease over a median time of 4.6 years. METHODS: Six patients presented with proteinuria, hypertension, and/or lower limb edema and underwent detailed clinical and laboratory investigations. RESULTS: A novel FGA gene mutation was identified in each case: 2 frameshift mutations F521Sfs*27 and G519Efs*30 and 4 single base substitutions G555F, E526K, E524K, R554H. In 5 subjects, extensive amyloid deposits were found solely within the glomeruli, which stained specifically with antibodies to fibrinogen A alpha chain, and in one of these cases, we found coexistent fibrinogen A alpha chain amyloidosis and anti-glomerular basement membrane antibody disease. One patient was diagnosed with light-chain amyloidosis after a bone marrow examination revealed a small clonal plasma cell population, and laser microdissection of the amyloid deposits followed by liquid chromatography and tandem mass spectrometry identified kappa light chain as the fibril protein. DISCUSSION: We report 6 novel mutations in the FGA gene: 5 were associated with renal fibrinogen A alpha chain amyloidosis and 1 was found to be incidental to light-chain amyloid deposits discovered in a patient with a plasma cell dyscrasia. Clinical awareness and suspicion of hereditary amyloidosis corroborated by genetic analysis and adequate typing using combined immunohistochemistry and laser microdissection and mass spectrometry is valuable to avoid misdiagnosis, especially when a family history of amyloidosis is absent.

Two male sibs with severe micrognathia and a missense variant in MED12.

Missense variants in MED12 cause three partially overlapping dysmorphic X-linked intellectual disability (XLID) syndromes: Lujan-Fryns syndrome (also known as Lujan syndrome), FG syndrome (also known as Opitz-Kaveggia syndrome) and X-linked Ohdo syndrome. We report a family with two severely micrognathic male sibs, a 10½ year old boy and a fetus, in which hemizygosity for a previously unreported missense variant in exon 13 of MED12 (NM_005120.2), c.1862G > A, p.(Arg621Gln) was detected by whole exome sequencing. The affected sibs shared no other rare variant with relevance to the phenotype. X-chromosome inactivation in blood was completely skewed (100:0) in the unaffected heterozygous mother, most likely as a result of preferential inactivation of the X-chromosome harbouring the missense variant in MED12. Neither the unaffected brother nor the unaffected maternal grandfather carried the missense variant in MED12. In the 10½ year old boy, upper airway obstruction secondary to Pierre Robin sequence necessitated a tracheostomy for the first 10 months of life. He has mild to moderate intellectual disability and some dysmorphic features seen in MED12-related syndromes. In addition, he has a horizontal gaze paresis, anomalies of the inner ear, and a cervical block vertebra. This report contributes to the expanding phenotypic range associated with MED12-mutations.

Nontesticular cancers in relatives of testicular germ cell tumor (TGCT) patients from multiple-case TGCT families.

Testicular germ cell tumors (TGCT) exhibit striking familial aggregation that remains incompletely explained. To improve the phenotypic definition of familial TGCT (FTGCT), we studied an international cohort of multiple-case TGCT families to determine whether first-degree relatives of FTGCT cases are at increased risk of other types of cancer. We identified 1041 first-degree relatives of TGCT cases in 66 multiple-case TGCT families from Norway and 64 from the United States (combined follow-up of 31,556 person-years). We collected data on all cancers (except nonmelanoma skin cancers) reported by the family informant in these relatives, and we attempted to verify all reported cancer diagnoses through medical or cancer registry records. We calculated observed-to-expected (O/E) standardized incidence ratios, together with 95% confidence intervals (CI), for invasive cancers other than TGCT. We found no increase in risk of cancer overall (Norway O/E = 0.8; 95% CI: 0.6-1.1 and United States O/E = 0.9; 95% CI: 0.7-1.3). Site-specific analyses pooled across the two countries revealed a leukemia excess (O/E = 6.5; 95% CI: 3.0-12.3), deficit of female breast cancer (O/E = 0.0; 95% CI: 0.0-0.6) and increased risk of soft tissue sarcoma (O/E = 7.2; 95% CI: 2.0-18.4); in all instances, these results were based on small case numbers and statistically significant only in Norway. While limited by sample size and potential issues relating to completeness of cancer reporting, this study in multiple-case TGCT families does not support the hypothesis that cancers other than testis cancer contribute to the FTGCT phenotype.

The cardiac phenotype in patients with a CHD7 mutation.

BACKGROUND: Loss-of-function mutations in CHD7 cause Coloboma, Heart Disease, Atresia of Choanae, Retardation of Growth and/or Development, Genital Hypoplasia, and Ear Abnormalities With or Without Deafness (CHARGE) syndrome, a variable combination of multiple congenital malformations including heart defects. Heart defects are reported in 70% to 92% of patients with a CHD7 mutation, but most studies are small and do not provide a detailed classification of the defects. We present the first, detailed, descriptive study on the cardiac phenotype of 299 patients with a CHD7 mutation and discuss the role of CHD7 in cardiac development. METHODS AND RESULTS: We collected information on congenital heart defects in 299 patients with a pathogenic CHD7 mutation, of whom 220 (74%) had a congenital heart defect. Detailed information on the heart defects was available for 202 of these patients. We classified the heart defects based on embryonic cardiac development and compared the distribution to 1007 equally classified nonsyndromic heart defects of patients registered by EUROCAT, a European Registry of Congenital Anomalies. Heart defects are highly variable in patients with CHD7 mutations, but atrioventricular septal defects and conotruncal heart defects are over-represented. Sex did not have an effect on the presence of heart defects, but truncating CHD7 mutations resulted in a heart defect significantly more often than missense or splice-site mutations (χ², P<0.001). CONCLUSIONS: CHD7 plays an important role in cardiac development, given that we found a wide range of heart defects in 74% of a large cohort of patients with a CHD7 mutation. Conotruncal defects and atrioventricular septal defects are over-represented in patients with CHD7 mutations compared with patients with nonsyndromic heart defects.

Germline PTEN mutations are rare and highly penetrant.

Cowden syndrome (multiple hamartoma syndrome, MIM 158350) is an early onset syndrome characterized by multiple hamartomas in the skin, mucous membranes, breast, thyroid and endometrium. Patients with Cowden syndrome have increased risk of breast cancer, thyroid cancer and endometrial cancer. In 1997 germline mutations in PTEN were demonstrated to cause Cowden syndrome. We report the results of diagnostic and predictive testing in all families with Cowden syndrome or suspected Cowden syndrome registered at the Norwegian cancer family clinics. PTEN mutations were found in all six families meeting the clinical criteria for Cowden syndrome, in none of the two families assumed to have Cowden syndrome but not fulfilling the criteria, and in none of the eight families selected in our computerized medical files to have a combination of breast and thyroid cancers. Age-related penetrances for the various neoplasms are given. All families but one were small and de novo mutations were found.