A deletion containing a CTCF-element in intron 8 of the Bbs7 gene is partially responsible for juvenile obesity in the Berlin Fat Mouse

The Berlin Fat Mouse Inbred (BFMI) line is a model for juvenile obesity. Previous studies on crosses between BFMI and C57Bl/6N (B6N) have identified a recessive defect causing juvenile obesity on chromosome 3 (jObes1). Bbs7 was identified as the most likely candidate gene for the observed effect. Comparative sequence analysis showed a 1578 bp deletion in intron 8 of Bbs7 in BFMI mice. A CTCF-element is located inside this deletion. To investigate the functional effect of this deletion, it was introduced into B6N mice using CRISPR/Cas9. Two mice containing the target deletion were obtained (B6N Bbs7emI8∆1 and Bbs7emI8∆2) and were subsequently mated to BFMI and B6N to generate two families suitable for complementation. Inherited alleles were determined and body composition was measured by quantitative magnetic resonance. Evidence for a partial complementation (13.1–15.1%) of the jObes1 allele by the CRISPR/Cas9 modified B6N Bbs7emI8∆1 and Bbs7emI8∆2 alleles was found. Mice carrying the complementation alleles had a 23–27% higher fat-to-lean ratio compared to animals which have a B6N allele (P(Bbs7emI8∆1) = 4.25 × 10–7; P(Bbs7emI8∆2) = 3.17 × 10–5). Consistent with previous findings, the recessive effect of the BFMI allele was also seen for the B6N Bbs7emI8∆1 and Bbs7emI8∆2 alleles. However, the effect size of the B6N Bbs7emI8∆1 and Bbs7emI8∆2 alleles was smaller than the BFMI allele, and thus showed only a partial complementation. Findings suggest additional variants near Bbs7 in addition to or interacting with the deletion in intron 8.

A Case of Pyruvate Carboxylase Deficiency With Longer Survival and Normal Laboratory Findings

Pyruvate carboxylase deficiency (PCD) is a rare autosomal recessive defect in a biotin-containing enzyme, Pyruvate carboxylase, which is considered as an enzyme of TCA-cycle regulation, gluconeogenesis, lipogenesis, and biosynthesis of neurotransmitters. Increased lactate to pyruvate ratio and decreased three hydroxybutyrates to acetoacetate are the main biochemical features of PCD. The elevated level of Citrulline, Proline, and Lysine with a short life span has been reported previously. Patients’ survival in almost all cases is below three months. Here, the authors aimed to report a girl with manifestations of Type B of PCD and longer survival (two-year and four-month-old). This patient did not have any changes in amino acid level, which was a unique case of Type B of PCD.

Severe High Molecular Weight Kininogen (HK) Deficiency: Clinical Characteristics, Deficiency-Causing KNG1 Variants in Reported and New Cases, and Estimated Prevalence

Background: Severe high molecular weight kininogen (HK) deficiency is an autosomal recessive defect of the contact system caused by mutations in KNG1. Limited scientific interest in HK deficiency due to the rarity of the seemingly asymptomatic condition may increase, as HK, the precursor of bradykinin, is now discussed as a therapeutic target e.g. in hereditary angioedema. Aims: We provide a comprehensive analysis of the diagnostic, clinical, and genetic features of HK deficiency and estimate its frequency. Methods: We identified a new case of HK deficiency, systematically review the literature, conduct new genetic studies of reported cases, and comprehensively analyze the clinical course and diagnostic criteria. Clotting activity of HK and prekallikrein (PK) (HK:C/PK:C) and antigen (HK:Ag/PK:Ag) were determined and genetic analyses of KNG1 and KLKB1 were performed by Sanger sequencing. Characteristics deduced from the known HK deficiency-causing variants were used to estimate the frequency of HK deficiency from the KNG1 variants aggregated in GnomAD. Results: 677 studies were identified by systematic review of the literature for HK deficiency. 27 of these contained individual cases of HK deficiency including 6 studies not listed in PubMed. Little-noticed cases from the gray literature account for more than one-third (16/39) of the extracted, unrelated cases. We genotyped one newly diagnosed HK-deficient case and 2 cases described in the literature and additionally evaluated all 10 studies reporting genetic data in HK-deficiency (including one case previously misdiagnosed as having PK deficiency). A total of 10 KNG1 variants causing HK deficiency (one new) were found, the most frequent being c.586C>T, p.Arg196* (4 unrelated families). Interestingly, all HK deficiency-causing variants are truncating, whereas two amino acid substitutions with presumed functional consequence, have been described as the cause of hereditary angioedema. Conservative prevalence estimates based on all known and putative HK deficiency-causing variants extracted from GnomAD (truncating variants in KNG1, including indels, nonsense and canonical splice site mutations located in that part of the gene, where relevant mutations have been described) revealed a frequency of 1 case of HK deficiency among 7,925,172 with slight differences in the analyzed ethnicities (see table). In addition, although not to the same extent as seen in PK deficiency, HK deficiency apparently is more prevalent in Africans. While it is already well known that HK deficiency causes decreased PK levels, our data indicate that factor XI levels are also frequently decreased, albeit to a lesser extent. The number of cases detected so far is too low for a more detailed analysis regarding bleeding, thrombotic, and cardiovascular events or immunological abnormalities. Conclusion: HK-deficiency is probably more frequent than previously thought. Suspected cases of contact phase defects should at least be analyzed for HK activity (besides factor XII, XI and PK activity) to facilitate conclusive evaluation of the clinical significance in the future. Figure 1 Figure 1. Disclosures Lämmle: Takeda: Membership on an entity's Board of Directors or advisory committees; Ablynx: Membership on an entity's Board of Directors or advisory committees, Other: Travel Support, Speakers Bureau; Baxter: Other: Travel Support, Speakers Bureau; Alexion: Other: Travel Support, Speakers Bureau; Siemens: Other: Travel Support, Speakers Bureau; Bayer: Other: Travel Support, Speakers Bureau; Roche: Other: Travel Support, Speakers Bureau; Sanofi: Other: Travel Support, Speakers Bureau.

Deletion of Mocos induces xanthinuria with obstructive nephropathy and major metabolic disorders in mice

Background: Xanthinuria type II is a rare autosomal purine disorder. This recessive defect of purine metabolism remains an underrecognized disorder. Methods: Mice with targeted disruption of the molybdenum cofactor sulfurase (Mocos) gene were generated to enable an integrated understanding of purine disorders and evaluate pathophysiological functions of this gene found in large number of pathways and known to be associated with autism. Results: Mocos deficient mice die with 4 weeks of age due to renal failure of distinct obstructive nephropathy with xanthinuria, xanthine deposits, cystic tublular dilatation, Tamm Horsfall (uromodulin) protein deposits, tubular cell necrosis with neutrophils and occasionally hypdronephrosis with urolithiasis. Obstructive nephropathy is associated with moderate interstitial inflammatory and fibrotic responses, anemia, reduced detoxification systems and important alterations of the metabolism of purines, amino acids and phospholipids.Conversely, heterozygous mice expressing reduced MOCOS protein are healthy with no apparent pathology. Conclusions: Mocos deficient mice develop a lethal obstructive nephropathy associated with profound metabolic changes. Studying MOCOS functions may provide important clues about the underlying pathogenesis of xanthinuria and other diseases requiring early diagnosis

Carnitine Palmitoyltranferase Type 1 Deficiency: A Case Report of Fatty Acid Oxidation Disorder Encephalopathy

Background: Carnitine palmitoyltransferase-1 (CPT-1) deficiency is a rare autosomal recessive disorder of mitochondrial long-chain fatty acid oxidation with fewer than 30 case reports. Case report: A 30-month-old child with fever and loss of consciousness was referred to our hospital. She had symptoms of colds for three days that were treated, but she had anorexia.Her abdomen was soft and hepatomegaly 5 cm below the edge of the rib was detected. According to a neurological consultation, with the probability of a seizure, the patient beganto receive levetiracetam. The patient was treated with sodium benzoate due to her decreased level of consciousness and increased blood ammonia (300). In the acylcarnitine profile, mildlyelevated levels of single acylcarnitine were seen to confirm the diagnosis of CPT-1 deficiency. Conclusions: CPT-1 deficiency is a rare autosomal recessive defect of mitochondrial longchain fatty acid oxidation that presents as an acute “Reye-like” hepatic encephalopathy andnon-ketotic hypoglycemia, developmental delay, and hepatomegaly.

Cholesterol deficiency haplotype frequency and its impact on milk production and milk cholesterol content in Canadian Holstein cows

An autosomal recessive defect caused by a loss of function mutation in the bovine apolipoprotein B (APOB) gene causes cholesterol deficiency with strong effects on calf survival and development. This study examined the distribution of cholesterol deficiency haplotype (CDH) in the APOB gene in Canadian Holstein cows and its impacts on milk production and milk cholesterol content. The CDH in 917 cows from 29 herds was determined via polymerase chain reaction (PCR). A longer insertion of approximately 7 kb potentially characterizing the mutation was amplified. The average carrier frequency of herds in Quebec based on PCR results was 14.6%. Cholesterol deficiency haplotype status had non-significant (P > 0.05) effects on milk cholesterol content, other milk components, and milk yield.

Prevalence of congenital non syndromic hearing loss among offspring of consanguineous marriage: a pilot study

<p class="abstract"><strong>Background:</strong> Mutations in the gene encoding the gap-junction protein connexin-26, is understood to be the most important cause of non-syndromic hearing loss (NSHL). An attempt to identify the single nucleotide polymorphism (SNP) for W24X mutation was done. Consanguineous marriage was seen among the NSHL subjects.</p><p class="abstract"><strong>Methods:</strong> SNP was identified using restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR). Forty-five subjects were screened for congenital hearing loss. Twenty subjects matched the inclusion criteria and were included in the study.</p><p class="abstract"><strong>Results:</strong> 5 out of 20 subjects were found to have mutation i.e., 25%. Though consanguinity is known to cause autosomal recessive defect, the same could not be depicted in this study.</p><p class="abstract"><strong>Conclusions:</strong> 25% of the study population had a mutation in their gene and the rest though had consanguineous marriage had not been affected genotypically.</p>

Familial case of Fryns syndrome in two fetuses in second trimester

Fryns syndrome (FS) is a multiple congenital anomaly syndrome, inherited as an autosomal recessive defect with diagnostic triad including diaphragmatic hernia, abnormal face, and distal limb anomalies. Two cases of FS in the fetuses, whose mother had previous affected pregnancy with the infant having diaphragmatic hernia are presented. Both fetuses have atypical limb deformity, ectrodactyly. These cases illustrate the spectrum of FS and the importance of a family history in fetuses with congenital diaphragmatic hernia.

Evidence of single point mutation inducing BLAD disease in Romanian Holstein-derived cattle breed

Bovine leukocyte adhesion deficiency (BLAD) is a genetic disease that affects the haematopoietic system via greatly reduced expression of the heterodimeric ?2 integrin, causing many defects in leukocyte function. It is known that BLAD is an autosomal recessive defect, caused by a point mutation in the gene encoding subunit CD18 for ?2 integrin adhesion molecule, which is lethal in the homozygous form. In this study, 80 cattle of the Romanian Black Spotted breed have been screened via the DNA test. We performed the PCR-RFLP test followed by sequencing to investigate the incidence of this genetic disease. A single point mutation was identified within the gene encoding bovine CD18 in two Romanian Black Spotted cattle affected with BLAD. The aim of our work was to optimize PCR (Polymerase Chain Reaction), RFLP (Restriction Fragment Length Polymorphism) and sequencing analysis as a diagnostic test to identify BLAD carrier cattle.

Androgen-receptor defect abolishes sex differences in nitric oxide and reactivity to vasopressin in rat aorta

Contractions of rat thoracic aorta to vasopressin (VP) are threefold higher in females (F) than in males (M), primarily because nitric oxide (NO) attenuation of contraction is greater in M. To determine the role of the androgen receptor (AR) in this mechanism, vascular reactivity to VP was examined in thoracic aorta of the testicular-feminized male (Tfm) rat, which has an X-linked, recessive defect in AR function in affected M. Maximal contraction of normal aortas to VP was fourfold higher in F (4,128 ± 291 mg/mg ring wt) than in M (971 ± 133 mg); maximal response of Tfm (3,967 ± 253 mg) was similar to that of normal F. N G-nitro-l-arginine methyl ester increased maximal response to VP threefold in M but had no effect in F or Tfm. In contrast, maximal contraction of normal aortas to phenylephrine was 43% higher in M (4,011 ± 179 mg) than in F (2,809 ± 78 mg); maximal response of Tfm (2,716 ± 126 mg) was similar to that of normal F. N G-nitro-l-arginine methyl ester increased maximal response to phenylephrine by >50% in F and Tfm but had no effect in M. Maximal contractile response to 80 mM KCl did not differ among M, F, or Tfm. Thus androgens and normal vascular AR function are important in the greater NO-mediated attenuation of reactivity to VP in M than in F rat aorta, which may involve specific modulation of endothelial VP signal transduction pathways and NO release by androgens. These data also establish the importance of the Tfm rat as a model to study the effects of androgens on cardiovascular function.