Arthrogryposis, perthes disease, and upward gaze palsy: a novel autosomal recessive syndromic form of arthrogryposis

In this article, the unusual combination of arthrogryposis, upward gaze palsy, and Perthes disease in two sisters and their cousin who are all part of an extended consanguineous Saudi family is reported. All patients had difficult to control bronchial asthma and subtle facial dysmorphism. Two of the three had pyloric stenosis, two were intellectually normal, and one had academic problems but had a history of birth hypoxia. Pedigree is consistent with an autosomal recessive mode of inheritance. Lack of previous reports suggests this represents a novel syndromic form of arthrogryposis.     

Exome sequencing reveals a novel Fanconi group defined by XRCC2 mutation

Background Fanconi anaemia (FA) is a group of disorders characterised by progressive bone marrow failure and a characteristic but variable craniofacial and skeletal involvement. Recessive mutations in any of 15 genes linked to FA lead to the pathognomonic increased susceptibility to double-strand DNA breaks. Methods Autozygome and exome analysis of a patient with classic FA phenotype Results The authors identified a novel truncating mutation in XRCC2. Consistent with the proposed causal link to FA, this gene is an essential non-redundant component of the RAD51 family of homologous repair proteins and its deficiency in a murine model has been shown to lead to a highly similar phenotype to that of this patient both at the cellular and organismal level. Conclusion This study implicates XRCC2 in the pathogenesis of FA and calls for further investigation of the potential contribution of XRCC2 mutations to the overall mutational load of FA.     

X-linked creatine transporter defect: A report on two unrelated boys with a severe clinical phenotype

Summary We report two unrelated boys with the X-linked creatine transporter defect (CRTR) and clinical features more severe than those previously described with this disorder. These two boys presented at ages 12 and 30 months with severe mental retardation, absent speech development, hypotonia, myopathy and extra-pyramidal movement disorder. One boy has seizures and some dysmorphic features; he also has evidence of an oxidative phosphorylation defect. They both had classical absence of creatine peak on brain magnetic resonance spectroscopy (MRS). In one, however, this critical finding was overlooked in the initial interpretation and was discovered upon subsequent review of the MRS. Molecular studies showed large genomic deletions of a large part of the 3′ end of the complete open reading frame of the SLC6A8 gene. This report emphasizes the importance of MRS in evaluating neurological symptoms, broadens the phenotypic spectrum of CRTR and adds knowledge about the pathogenesis of creatine depletion in the brain and retina. First and second author contributed equally to this paper Communicating editor: Michael Gibson Competing interests: None declared An erratum to this article is available at .     

Familial non-syndromic macular pseudocoloboma secondary to homozygous CLDN19 mutation

Purpose: The purpose of this study is to uncover the genetic cause for non-syndromic macular “coloboma” (pseudocoloboma) in three brothers from a consanguineous family.

Methods: Homozygosity mapping for the three affected brothers and whole-exome sequencing in one affected brother, followed by confirmatory Sanger sequencing and segregation analysis of the candidate gene for all immediate family members; molecular modeling of the candidate mutation; and review of clinical, imaging, and laboratory findings.

Results: Three otherwise-healthy brothers (age 10, 10, and 6 years) had macular pseudocoloboma. Both parents and the fourth brother were not affected. Parents were first cousins. A novel homozygous missense variant in claudin 19 (CLND19: NM_148960.2:c. 263T>A; p.Val88Glu) segregated with the phenotype, and molecular modeling predicts an unfavorable effect to protein function. All prior reported biallelic CLND19 mutations cause symptomatic hypomagnesemia with hypercalciuria and nephrocalcinosis, often with concurrent macular pseudocoloboma. However, general physical assessment, metabolic profile, and renal imaging for the three affected brothers were normal.

Conclusions: A homozygous CLDN19 mutation can cause macular pseudocoloboma without evidence for systemic disease in children. This is the first reported family with CLDN19 mutations to have an ocular phenotype only; however, those identified to harbor biallelic CLDN19 mutations should be considered at risk for the extraocular manifestations that have previously been associated with mutations in the gene.     

Identification of differentially expressed proteins in the aqueous humor of primary congenital glaucoma

Primary Congenital Glaucoma (PCG) is an autosomal recessive disease caused by an abnormal development of the anterior chamber angle. Although, PCG has been linked to several genetic loci, the role that the genes at these loci or their encoded proteins play in the pathophysiology of PCG and development of the anterior chamber is not known. To identify proteins that may be altered in PCG and that may help in understanding the underlying pathophysiology of the disease, we took a global proteomics approach. Tryptic digests of the complex mixtures of proteins in aqueous humor were analyzed using Liquid Chromatography/Mass Spectrometry (LC-MS/MS). Proteins were identified by searching the data against the human subset of the UniProt database. The proteomes of aqueous humor in PCG (n = 7) and patients undergoing cataract surgery as control (n = 4) were compared based on the scan counts of comparable proteins. Using stringent filtering criteria, Apolipoprotein A-IV (APOA-IV), Albumin and Antithrombin 3 (ANT3) were detected at significantly higher levels in PCG AH compared to control, whereas Transthyretin (TTR), Prostaglandin-H2 D-isomerase (PTGDS), Opticin (OPT) and Interphotoreceptor Retinoid Binding Protein (IRBP) were detected at significantly lower levels. Many of these proteins play a role in retinoic acid (RA) binding/transport and have been implicated in the pathogenesis of neurodegenerative diseases such as Alzheimer’s (AD). It is possible that similar to AD, the pathologic changes in PCG during development could be influenced by the availability of RA in the anterior chamber.     

Ocular manifestations in Kabuki syndrome: the first report from Saudi Arabia

Background: Kabuki syndrome (KS) is a multiple congenital anomaly syndrome in which ophthalmological examination for the early detection of ocular abnormalities is desired in order to prevent visual impairment. Case: Retrospective, interventional, case report of a 5-year-old female patient of Arabic origin with features of Kabuki syndrome. Observation: Patient had neurological deficit, psychomotor retardation, a peculiar face, including large prominent cup shaped ears, broad depressed nasal tip, and high arched palate, and malformed teeth. Her ocular features suggestive of Kabuki syndrome included left upper eyelid congenital ptosis, lagophthalmos, arched eyebrows with temporal sparing of hair, long horizontal palpebral fissures, lateral lower eyelid eversion and resultant epiphora. Other abnormalities included medial lower epicanthal folds, abduction deficit bilaterally, large esotropia, significant hyperopia, right corneal opacity, iris and chorioretinal coloboma. Patient required hyperopic correction and ptosis surgery, which improved her visual functioning. Conclusions: We report the first case of a Kabuki syndrome patient from Saudi Arabia and stress on the importance of ophthalmological examination in all patients with KS for the early detection of ocular anomalies in order to prevent visual impairment.     

A patient with a ring chromosome 2 and microdeletion of 2q detected using FISH: Further support for "ring chromosome 2 syndrome"

Bifid epiglottis is a rare anomaly, which is heterogeneous and is often associated with other anomalies, particularly polydactyly. It has been reported in 40% of patients with Pallister-Hall syndrome and rarely in other syndromes. We report two brothers with bifid epiglottis who also have features suggestive of Bardet-Biedl syndrome. We also review the features seen in 22 patients reported in the literature with bifid epiglottis. No patient had bifid epiglottis as an isolated anomaly. Other malformations include clefts, micropenis, renal abnormalities, anal malformations, hypospadias, hypothalamic hamartomas, hypopituitarism, heart defects, and Hirschprung disease. Bifid epiglottis may be an under-recognized feature of Bardet-Biedl syndrome and should be considered in these patients, particularly if there are airway symptoms. Many of the anomalies associated with bifid epiglottis have potentially serious consequences and thus, a thorough evaluation of the patient with bifid epiglottis is warranted.     

3-Methylglutaconic aciduria—lessons from 50 genes and 977 patients

Elevated urinary excretion of 3-methylglutaconic acid is considered rare in patients suspected of a metabolic disorder. In 3-methylglutaconyl-CoA hydratase deficiency (mutations in AUH), it derives from leucine degradation. In all other disorders with 3-methylglutaconic aciduria the origin is unknown, yet mitochondrial dysfunction is thought to be the common denominator. We investigate the biochemical, clinical and genetic data of 388 patients referred to our centre under suspicion of a metabolic disorder showing 3-methylglutaconic aciduria in routine metabolic screening. Furthermore, we investigate 591 patients with 50 different, genetically proven, mitochondrial disorders for the presence of 3-methylglutaconic aciduria. Three percent of all urine samples of the patients referred showed 3-methylglutaconic aciduria, often in correlation with disorders not reported earlier in association with 3-methylglutaconic aciduria (e.g. organic acidurias, urea cycle disorders, haematological and neuromuscular disorders). In the patient cohort with genetically proven mitochondrial disorders 11 % presented 3-methylglutaconic aciduria. It was more frequently seen in ATPase related disorders, with mitochondrial DNA depletion or deletion, but not in patients with single respiratory chain complex deficiencies. Besides, it was a consistent feature of patients with mutations in TAZ, SERAC1, OPA3, DNAJC19 and TMEM70 accounting for mitochondrial membrane related pathology. 3-methylglutaconic aciduria is found quite frequently in patients suspected of a metabolic disorder, and mitochondrial dysfunction is indeed a common denominator. It is only a discriminative feature of patients with mutations in AUH, TAZ, SERAC1, OPA3, DNAJC19 TMEM70. These conditions should therefore be referred to as inborn errors of metabolism with 3-methylglutaconic aciduria as discriminative feature.