37 research outputs found
Recommended from our members
O23: Diagnostic success of genomic analyses in adults with undiagnosed diseases: A report from the Undiagnosed Diseases Network (UDN)
Recommended from our members
P458: EFEMP1 haploinsufficiency causes a Marfan-like hereditary connective tissue disorder
Recommended from our members
Bilateral choanal stenosis in auriculocondylar syndrome caused by a PLCB4 variant
Auriculocondylar syndrome (ARCND) is characterized by a distinguished feature of question mark ears and a variation of other minor and major malformations. Monoallelic or biallelic PLCB4 variants have been reported in a subset of affected individuals, referred to as ARCND2. We report on a 3-year-old female with ARCND who presented at birth with question mark ears, micrognathia, and bilateral choanal stenosis that was characterized by difficulty in breathing. She was found to be heterozygous for a novel PLCB4 variant, p.Glu358Gly. Respiratory distress is rare in autosomal dominant ARCND2 and choanal stenosis has not been reported. Our study expands the clinical phenotype of ARCND by adding choanal stenosis as a finding and suggests that PLCB4 play a role in the development of choanal structures
Recommended from our members
EFEMP1 haploinsufficiency causes a Marfan-like hereditary connective tissue disorder
Phenotypic features of a hereditary connective tissue disorder, including craniofacial characteristics, hyperextensible skin, joint laxity, kyphoscoliosis, arachnodactyly, inguinal hernia, and diverticulosis associated with biallelic pathogenic variants in EFEMP1 have been previously described in four patients. Genome sequencing on a proband and her mother with comparable phenotypic features revealed that both patients were heterozygous for a stop-gain variant c.1084C>T (p.Arg362*). Complementary RNA-seq on fibroblasts revealed significantly reduced levels of mutant EFEMP1 transcript. Considering the absence of other molecular explanations, we extrapolated that EFEMP1 could be the cause of the patient's phenotypes. Furthermore, nonsense-mediated decay was demonstrated for the mutant allele as the principal mechanism for decreased levels of EFEMP1 mRNA. We provide strong clinical and genetic evidence for the haploinsufficiency of EFEMP1 due to nonsense-medicated decay to cause severe kyphoscoliosis, generalized hypermobility of joints, high and narrow arched palate, and potentially severe diverticulosis. To the best of our knowledge, this is the first report of an autosomal dominant EFEMP1-associated hereditary connective tissue disorder and therefore expands the phenotypic spectrum of EFEMP1 related disorders
Recommended from our members
H4C5 missense variant leads to a neurodevelopmental phenotype overlapping with Angelman syndrome
Recurrent de novo missense variants in H4 histone genes have recently been associated with a novel neurodevelopmental syndrome that is characterized by intellectual disability and developmental delay as well as more variable findings that include short stature, microcephaly, and facial dysmorphisms. A 4-year-old male with autism, developmental delay, microcephaly, and a happy demeanor underwent evaluation through the Undiagnosed Disease Network. He was clinically suspected to have Angelman syndrome; however, molecular testing was negative. Genome sequencing identified the H4 histone gene variant H4C5 NM_003545.4: c.295T>C, p.Tyr99His, which parental testing confirmed to be de novo. The variant met criteria for a likely pathogenic classification and is one of the seven known disease-causing missense variants in H4C5. A comparison of our proband's findings to the initial description of the H4-associated neurodevelopmental syndrome demonstrates that his phenotype closely matches the spectrum of those reported among the 29 affected individuals. As such, this report corroborates the delineation of neurodevelopmental syndrome caused by de novo missense H4 gene variants. Moreover, it suggests that cases of clinically suspected Angelman syndrome without molecular confirmation should undergo exome or genome sequencing, as novel neurodevelopmental syndromes with phenotypes overlapping with Angelman continue to be discovered
Recommended from our members
Genome sequencing reveals novel noncoding variants in PLA2G6 and LMNB1 causing progressive neurologic disease
Neurodegenerative disorders and leukodystrophies are progressive neurologic conditions that can occur following the disruption of intricately coordinated patterns of gene expression. Exome sequencing has been adopted as an effective diagnostic tool for determining the underlying genetic etiology of Mendelian neurologic disorders, however genome sequencing offer advantages in its ability to identify and characterize copy number, structural, and sequence variants in noncoding regions. Genome sequencing from peripheral leukocytes was performed on two patients with progressive neurologic disease of unknown etiology following negative genetic investigations including exome sequencing. RNA sequencing from peripheral blood was performed to determine gene expression patterns in one of the patients. Potential causative variants were matched to the patients' clinical presentation. The first proband was found to be heterozygous for a likely pathogenic missense variant in PLA2G6 (c.386T>C; p.Leu129Pro) and have an additional deep intronic variant in PLA2G6 (c.2035-926G>A). RNA sequencing indicated this latter variant created a splice acceptor site leading to the incorporation of a pseudo-exon introducing a premature termination codon. The second proband was heterozygous for a 261 kb deletion upstream of LMNB1 that included an enhancer region. Previous reports of copy number variants spanning this region of cis-acting regulatory elements corroborated its pathogenicity. When combined with clinical presentations, these findings led to a definitive diagnosis of autosomal recessive infantile neuroaxonal dystrophy and autosomal dominant adult-onset demyelinating leukodystrophy, respectively. In patients with progressive neurologic disease of unknown etiology, genome sequencing with the addition of RNA analysis where appropriate should be considered for the identification of causative noncoding pathogenic variants
Recommended from our members
P121: Comparison of diagnostic outcome amongst different ethnic backgrounds in UDN participants at the University of Miami clinical site
Recommended from our members