KBG syndrome presenting with brachydactyly type E

We report the case of a young woman who presented at age 10 years with height on the tenth centile, brachydactyly type E and mild developmental delay. Biochemistry and hormonal profiles were normal. Differential diagnoses considered included Albright hereditary osteodystrophy without hormone resistance (a.k.a pseudopseudohypoparathyroidism), 2q37 microdeletion syndrome and acrodysostosis. She had a normal karyotype and normal FISH of 2q37. Whole genome sequencing (WGS) identified a mutation in the ANKRD11 gene associated with KBG syndrome. We review the clinical features of the genetic syndromes considered, and suggest KBG syndrome be considered in patients presenting with syndromic brachydactyly type E, especially if short stature and developmental delay are also present

A detailed phenotypic assessment of individuals affected by MFRP-related oculopathy

Purpose: To determine the spectrum of mutations and phenotypic variability within patients with mutations in membrane-type frizzled related protein gene (MFRP).Methods: Individuals were initially ascertained based on a phenotype similar to that previously published in association with MFRP mutations. Affected patients underwent a full ophthalmic examination (best-corrected visual acuity, slit-lamp examination, applanation tonometry, and fundoscopy), color fundus photography, optical coherence tomography, autofluorescence imaging, and electrophysiology. MFRP was identified by a genome-wide scan in the fourth-largest autozygous region in one consanguineous family. Sanger sequencing of all the exons and intron-exon boundaries of MFRP was undertaken in the affected individuals.Results: Seven affected individuals from four families were identified as having mutations in MFRP. Patients from two families were homozygous for mutations already previously described (c. 1143_1144 insC and c. 492 delC), while those from the other two were compound heterozygous for mutations (c. 201G>A and c. 491_492 insT, and c. 492 delC, and c. 1622_1625 delTCTG), three of which were novel. There was considerable phenotypic variability within and among families. Autofluorescence imaging revealed the central macula to be relatively well preserved. Foveal cysts and optic nerve head drusen were present in two of the four families. Electrophysiology results showed rod-cone dystrophy with mild to moderate reduction in macular function in all affected members.Conclusions: We report three novel MFRP mutations and expand the phenotypic data available on patients with MFRP mutations

A novel synonymous KMT2B variant in a patient with dystonia causes aberrant splicing

BACKGROUND: Heterozygous KMT2B variants are a common cause of dystonia. A novel synonymous KMT2B variant, c.5073C>T (p.Gly1691=) was identified in an individual with childhood-onset progressive dystonia. METHODS: The splicing impact of c.5073C>T was assessed using an in vitro exon-trapping assay. The genomic region of KMT2B exons 23-26 was cloned into the pSpliceExpress plasmid between exon 2 and 3 of the rat Ins2 gene. The c.5073C>T variant was then introduced through site-directed mutagenesis. The KMT2B wild-type and c.5073C>T plasmids were transfected separately into HeLa cells and RNA was extracted 48 hours after transfection. The RNA was reverse transcribed to produce cDNA, which was PCR amplified using primers annealing to the flanking rat Ins2 sequences. RESULTS: Sanger sequencing of the PCR products revealed that c.5073C>T caused a novel splice donor site and therefore a 5-bp deletion of KMT2B exon 23 in mature mRNA, leading to a coding frameshift and premature stop codon (p.Lys1692AsnfsTer7). CONCLUSION: To our knowledge, this is the first report of a KMT2B synonymous variant associated with dystonia. Reassessment of synonymous variants may increase diagnostic yield for inherited disorders including monogenic dystonia. This is of clinical importance, given the generally favourable response to deep brain stimulation for KMT2B-related dystonia

Herd-level animal management factors associated with the occurrence of bovine neonatal pancytopenia in calves in a multicountry study

Since 2007, mortality associated with a previously unreported haemorrhagic disease has been observed in young calves in several European countries. The syndrome, which has been named ‘bovine neonatal pancytopenia’ (BNP), is characterised by thrombocytopenia, leukocytopenia and a panmyelophthisis. A herd-level case-control study was conducted in four BNP affected countries (Belgium, France, Germany and the Netherlands) to identify herd management risk factors for BNP occurrence. Data were collected using structured face-to-face and telephone interviews of farm managers and their local veterinarians. In total, 363 case farms and 887 control farms were included in a matched multivariable conditional logistic regression analysis. Case-control status was strongly associated with the odds of herd level use of the vaccine PregSure® BVD (PregSure, Pfizer Animal Health) (matched adjusted odds ratio (OR) 107.2; 95% CI: 41.0–280.1). This was also the case for the practices of feeding calves colostrum from the calf’s own dam (OR 2.0; 95% CI: 1.1–3.4) or feeding pooled colostrum (OR 4.1; 95% CI: 1.9–8.8). Given that the study had relatively high statistical power and represented a variety of cattle production and husbandry systems, it can be concluded with some confidence that no other herd level management factors are competent causes for a sufficient cause of BNP occurrence on herd level. It is suggested that genetic characteristics of the dams and BNP calves should be the focus of further investigations aimed at identifying the currently missing component causes that together with PregSure vaccination and colostrum feeding represent a sufficient cause for occurrence of BNP in calves

Biochemical evidence for the tyrosine involvement in cationic intermediate stabilization in mouse β-carotene 15, 15'-monooxygenase

<p>Abstract</p> <p>Background</p> <p>β-carotene 15,15'-monooxygenase (BCMO1) catalyzes the crucial first step in vitamin A biosynthesis in animals. We wished to explore the possibility that a carbocation intermediate is formed during the cleavage reaction of BCMO1, as is seen for many isoprenoid biosynthesis enzymes, and to determine which residues in the substrate binding cleft are necessary for catalytic and substrate binding activity. To test this hypothesis, we replaced substrate cleft aromatic and acidic residues by site-directed mutagenesis. Enzymatic activity was measured <it>in vitro </it>using His-tag purified proteins and <it>in vivo </it>in a β-carotene-accumulating <it>E. coli </it>system.</p> <p>Results</p> <p>Our assays show that mutation of either Y235 or Y326 to leucine (no cation-π stabilization) significantly impairs the catalytic activity of the enzyme. Moreover, mutation of Y326 to glutamine (predicted to destabilize a putative carbocation) almost eliminates activity (9.3% of wt activity). However, replacement of these same tyrosines with phenylalanine or tryptophan does not significantly impair activity, indicating that aromaticity at these residues is crucial. Mutations of two other aromatic residues in the binding cleft of BCMO1, F51 and W454, to either another aromatic residue or to leucine do not influence the catalytic activity of the enzyme. Our <it>ab initio </it>model of BCMO1 with β-carotene mounted supports a mechanism involving cation-π stabilization by Y235 and Y326.</p> <p>Conclusions</p> <p>Our data are consistent with the formation of a substrate carbocation intermediate and cation-π stabilization of this intermediate by two aromatic residues in the substrate-binding cleft of BCMO1.</p