A novel TTC26 variant in a patient with hexadactyly, pituitary stalk interruption, hepatopathy, nephropathy, and bilateral lip-palate cleft: A case report and expansion of the phenotype.

Biallelic pathogenic variants in the TTC26 gene are known to cause BRENS (biliary, renal, neurological, skeletal) syndrome, an ultra-rare autosomal recessive condition with only few patients published to date. BRENS syndrome is characterized by hexadactyly, severe neonatal cholestasis, and involvement of the brain, heart, and kidney, however the full phenotypic and genotypic spectrum is unknown. Here, we report on a previously undescribed homozygous intronic TTC26 variant (c.1006-5 T > C) in a patient showing some of the known TTC26-associated features like hexadactyly, hypopituitarism, hepatopathy, nephropathy, and congenital heart defect. Moreover, he presented with a suspected unilateral hearing loss and bilateral cleft lip-palate. The variant is considered to affect correct splicing by the loss of the canonical acceptor splice site and activation of a cryptic acceptor splice site. Hereby, our patient represents one additional patient with BRENS syndrome carrying a previously unreported TTC26 variant. Furthermore, we confirm the involvement of the pituitary gland to be a common clinical feature of the syndrome and broaden the clinical spectrum of TTC26 ciliopathy to include facial clefts and a probable hearing involvement.

Siblings with Gorlin-Goltz syndrome associated with cardiac tumors: a case report and review of literature.

Primary cardiac tumors in children are very rare and may be associated with severe arrhythmias and sudden infant death syndrome. These cardiac arrhythmias vary depending on the location and size of the tumor. Sixty-four percent of children with cardiac fibroma, the second most common benign cardiac tumor in children, have ventricular arrhythmias, affecting therapeutic management and risk profile of these children. We report on two siblings with cardiac fibromas whose clinical presentations differed depending on their locations and size of the tumors. The first child, a three-year-old girl, was diagnosed with a cardiac fibroma in the left ventricle at the age of 8 months after surviving resuscitation due to ventricular fibrillation. Secondary prophylactic implantation of an ICD was performed. On propranolol, no further malignant arrhythmias have occurred to date. The seven-month-old brother was diagnosed postnatally with a cardiac tumor adjacent to the right ventricle. A few weeks after birth, the boy had refractory supraventricular tachycardia and ventricular arrhythmia that only resolved with amiodarone. In genetic testing, Gorlin-Goltz syndrome was diagnosed in both children. Conservative pharmacological therapy is a therapeutic strategy for asymptomatic patients with cardiac fibromas. The anti-arrhythmic medication depends on the location of the tumor. Implantation of an ICD should be performed in cases of malignant arrhythmias. In rare cases, there is an association between cardiac tumors and genetic syndromes, such as Gorlin-Goltz syndrome. These should always be considered when such a tumor is diagnosed.

Case Report of a DDX41 Germline Mutation in a Family with Multiple Relatives Suffering from Leukemia.

INTRODUCTION: Previously, it was assumed that genetic influence played a minor role in acute myeloid leukemia (AML). Increasing evidence of germline mutations has emerged, such as DDX41 germline mutation associated with familial AML. CASE PRESENTATION: A 64-year-old male patient presented with reduced exercise tolerance and shortness of breath. Following confirmation of AML diagnosis, the patient was enrolled into the AMLSG-30-18 study with a requirement for allogenic stem cell transplantation. The sister was initially selected as a fully HLA-matched donor. However, the family history showed risks for familial AML. Due to the striking family history, further diagnostic steps were initiated to detect a germline mutation. METHODS: Using NGS in the patients' bone marrow AML sample, a DDX41 mutation with a VAF of 49% was detected, raising the possibility of a germline mutation. DNA from cheek swabs and eyebrows were tested for the presence of the DDX41 mutation in all siblings. RESULTS: DDX41 germline mutation was detected in 5 out of 6 siblings. The sister was excluded as a related donor and the search for an unrelated donor was initiated. CONCLUSION: Obtaining family history of cancer patients plays a crucial role in oncology. If a germline mutation is suspected, further family work-up should be initiated.

First step towards a consensus strategy for multi-locus diagnostic testing of imprinting disorders.

BACKGROUND: Imprinting disorders, which affect growth, development, metabolism and neoplasia risk, are caused by genetic or epigenetic changes to genes that are expressed from only one parental allele. Disease may result from changes in coding sequences, copy number changes, uniparental disomy or imprinting defects. Some imprinting disorders are clinically heterogeneous, some are associated with more than one imprinted locus, and some patients have alterations affecting multiple loci. Most imprinting disorders are diagnosed by stepwise analysis of gene dosage and methylation of single loci, but some laboratories assay a panel of loci associated with different imprinting disorders. We looked into the experience of several laboratories using single-locus and/or multi-locus diagnostic testing to explore how different testing strategies affect diagnostic outcomes and whether multi-locus testing has the potential to increase the diagnostic efficiency or reveal unforeseen diagnoses. RESULTS: We collected data from 11 laboratories in seven countries, involving 16,364 individuals and eight imprinting disorders. Among the 4721 individuals tested for the growth restriction disorder Silver-Russell syndrome, 731 had changes on chromosomes 7 and 11 classically associated with the disorder, but 115 had unexpected diagnoses that involved atypical molecular changes, imprinted loci on chromosomes other than 7 or 11 or multi-locus imprinting disorder. In a similar way, the molecular changes detected in Beckwith-Wiedemann syndrome and other imprinting disorders depended on the testing strategies employed by the different laboratories. CONCLUSIONS: Based on our findings, we discuss how multi-locus testing might optimise diagnosis for patients with classical and less familiar clinical imprinting disorders. Additionally, our compiled data reflect the daily life experiences of diagnostic laboratories, with a lower diagnostic yield than in clinically well-characterised cohorts, and illustrate the need for systematising clinical and molecular data.