ABSTRACT
Verheij syndrome (VRJS) is a rare craniofacial spliceosomopathy presenting with craniofacial dysmorphism, multiple congenital anomalies and variable neurodevelopmental delay. It is caused by single nucleotide variants (SNVs) in PUF60 or interstitial deletions of the 8q24.3 region. PUF60 encodes a splicing factor which forms part of the spliceosome. To date, 36 patients with a sole diagnosis of VRJS due to disease-causing PUF60 SNVs have been reported in peer-reviewed publications. Although the depth of their phenotyping has varied greatly, they exhibit marked phenotypic heterogeneity. We report 10 additional unrelated patients, including the first described patients of Khmer, Indian, and Vietnamese ethnicities, and the eldest patient to date, with 10 heterozygous PUF60 variants identified through exome sequencing, 8 previously unreported. All patients underwent deep phenotyping identifying variable dysmorphism, growth delay, neurodevelopmental delay, and multiple congenital anomalies, including several unique features. The eldest patient is the only reported individual with a germline variant and neither neurodevelopmental delay nor intellectual disability. In combining these detailed phenotypic data with that of previously reported patients (n = 46), we further refine the known frequencies of features associated with VRJS. These include neurodevelopmental delay/intellectual disability (98%), axial skeletal anomalies (74%), appendicular skeletal anomalies (73%), oral anomalies (68%), short stature (66%), cardiac anomalies (63%), brain malformations (48%), hearing loss (46%), microcephaly (41%), colobomata (38%), and other ocular anomalies (65%). This case series, incorporating three patients from previously unreported ethnic backgrounds, further delineates the broad pleiotropy and mutational spectrum of PUF60 pathogenic variants.
Subject(s)
Abnormalities, Multiple , Intellectual Disability , Microcephaly , RNA Splicing Factors , Repressor Proteins , Humans , Abnormalities, Multiple/diagnosis , Abnormalities, Multiple/genetics , Intellectual Disability/diagnosis , Intellectual Disability/genetics , Microcephaly/diagnosis , Microcephaly/genetics , Phenotype , Repressor Proteins/genetics , RNA Splicing Factors/genetics , Spliceosomes/genetics , Spliceosomes/pathologyABSTRACT
The Ts65Dn mouse is the most widely investigated segmentally trisomic mouse model of Down syndrome. Quantitative PCR based methods are the preferred way of detecting the trisomic segment for genotyping purposes. However, identification of a 1.5 fold difference in target DNA is at the limit of detection of most quantitative PCR based methods, and in practice this can lead to difficulties in assigning genotypes. We report a 100% accurate multiplex ligation-dependent probe amplification (MLPA) assay for genotyping the Ts65Dn mouse that is also applicable to all other segmentally trisomic mouse models of Down syndrome.
