Genetic and clinical landscape of childhood cerebellar hypoplasia and atrophy.

PURPOSE: Cerebellar hypoplasia and atrophy (CBHA) in children is an extremely heterogeneous group of disorders, but few comprehensive genetic studies have been reported. Comprehensive genetic analysis of CBHA patients may help differentiating atrophy and hypoplasia and potentially improve their prognostic aspects. METHODS: Patients with CBHA in 176 families were genetically examined using exome sequencing. Patients with disease-causing variants were clinically evaluated. RESULTS: Disease-causing variants were identified in 96 of the 176 families (54.5%). After excluding 6 families, 48 patients from 42 families were categorized as having syndromic associations with CBHA, whereas the remaining 51 patients from 48 families had isolated CBHA. In 51 patients, 26 aberrant genes were identified, of which, 20 (76.9%) caused disease in 1 family each. The most prevalent genes were CACNA1A, ITPR1, and KIF1A. Of the 26 aberrant genes, 21 and 1 were functionally annotated to atrophy and hypoplasia, respectively. CBHA+S was more clinically severe than CBHA-S. Notably, ARG1 and FOLR1 variants were identified in 2 families, leading to medical treatments. CONCLUSION: A wide genetic and clinical diversity of CBHA was revealed through exome sequencing in this cohort, which highlights the importance of comprehensive genetic analyses. Furthermore, molecular-based treatment was available for 2 families.

Clinical manifestation and long-term outcome of citrin deficiency: Report from a nationwide study in Japan.

Citrin deficiency is an autosomal recessive disorder caused by mutations in the SLC25A13 gene. The disease can present with age-dependent clinical manifestations: neonatal intrahepatic cholestasis by citrin deficiency (NICCD), failure to thrive, and dyslipidemia by citrin deficiency (FTTDCD), and adult-onset type II citrullinemia (CTLN2). As a nationwide study to investigate the clinical manifestations, medical therapy, and long-term outcome in Japanese patients with citrin deficiency, we collected clinical data of 222 patients diagnosed and/or treated at various different institutions between January 2000 and December 2019. In the entire cohort, 218 patients were alive while 4 patients (1 FTTDCD and 3 CTLN2) had died. All patients <20 years were alive. Patients with citrin deficiency had an increased risk for low weight and length at birth, and CTLN2 patients had an increased risk for growth impairment during adolescence. Liver transplantation has been performed in only 4 patients (1 NICCD, 3 CTLN2) with a good response thereafter. This study reports the diagnosis and clinical course in a large cohort of patients with citrin deficiency and suggests that early intervention including a low carbohydrate diet and MCT supplementation can be associated with improved clinical course and long-term outcome.

Food Preferences of Patients with Citrin Deficiency.

Citrin deficiency is characterized by a wide range of symptoms from infancy through adulthood and presents a distinct preference for a diet composed of high protein, high fat, and low carbohydrate. The present study elucidates the important criteria by patients with citrin deficiency for food selection through detailed analysis of their food preferences. The survey was conducted in 70 citrin-deficient patients aged 2-63 years and 55 control subjects aged 2-74 years and inquired about their preference for 435 food items using a scale of 1-4 (the higher, the more favored). The results showed that the foods marked as "dislike" accounted for 36.5% in the patient group, significantly higher than the 16.0% in the controls. The results also showed that patients clearly disliked foods with 20-24 (% of energy) or less protein, 45-54% (of energy) or less fat, and 30-39% (of energy) or more carbohydrate. Multiple regression analysis showed carbohydrates had the strongest influence on patients' food preference (ß = -0.503). It also showed female patients had a stronger aversion to foods with high carbohydrates than males. The protein, fat, and carbohydrate energy ratio (PFC) of highly favored foods among patients was almost the same as the average PFC ratio of their daily diet (protein 20-22: fat 47-51: carbohydrates 28-32). The data strongly suggest that from early infancy, patients start aspiring to a nutritional balance that can compensate for the metabolism dissonance caused by citrin deficiency in every food.

Analysis of daily energy, protein, fat, and carbohydrate intake in citrin-deficient patients: Towards prevention of adult-onset type II citrullinemia.

Patients with citrin deficiency during the adaptation/compensation period exhibit diverse clinical features and have characteristic diet of high protein, high fat, and low carbohydrate. Japanese cuisine typically contains high carbohydrate but evaluation of diet of citrin-deficient patients in 2008 showed a low energy intake and a protein:fat:carbohydrate (PFC) ratio of 19:44:37, which indicates low carbohydrate consumption rate. These findings prompted the need for diet intervention to prevent the adult onset of type II citrullinemia (CTLN2). Since the publication of the report about 10 years ago, patients are generally advised to eat what they wish under active dietary consultation and intervention. In this study, citrin-deficient patients and control subjects living in the same household provided answers to a questionnaire, filled-up a maximum 6-day food diary, and supplied physical data and information on medications if any. To study the effects of the current diet, the survey collected data from 62 patients and 45 controls comparing daily intakes of energy, protein, fat, and carbohydrate. Food analysis showed that patient's energy intake was 115% compared to the Japanese standard. The confidence interval of the PFC ratio of patients was 20-22:47-51:28-32, indicating higher protein, higher fat and lower carbohydrate relative to previous reports. The mean PFC ratio of female patients (22:53:25) was significantly different from that of male patients (20:46:34), which may explain the lower frequency of CTLN2 in females. Comparison of the present data to those published 10 years ago, energy, protein, and fat intakes were significantly higher but the amount of carbohydrate consumption remained the same. Regardless of age, most patients (except for adolescents) consumed 100-200 g/day of carbohydrates, which met the estimated average requirement of 100 g/day for healthy individuals. Finally, patients were generally not overweight and some CTLN2 patients were underweight although their energy intake was higher compared with the control subjects. We speculate that high-energy of a low carbohydrate diet under dietary intervention may help citrin-deficient patients attain normal growth and prevent the onset of CTLN2.

Digenic mutations in ALDH2 and ADH5 impair formaldehyde clearance and cause a multisystem disorder, AMeD syndrome.

Rs671 in the aldehyde dehydrogenase 2 gene (ALDH2) is the cause of Asian alcohol flushing response after drinking. ALDH2 detoxifies endogenous aldehydes, which are the major source of DNA damage repaired by the Fanconi anemia pathway. Here, we show that the rs671 defective allele in combination with mutations in the alcohol dehydrogenase 5 gene, which encodes formaldehyde dehydrogenase (ADH5FDH ), causes a previously unidentified disorder, AMeD (aplastic anemia, mental retardation, and dwarfism) syndrome. Cellular studies revealed that a decrease in the formaldehyde tolerance underlies a loss of differentiation and proliferation capacity of hematopoietic stem cells. Moreover, Adh5-/-Aldh2 E506K/E506K double-deficient mice recapitulated key clinical features of AMeDS, showing short life span, dwarfism, and hematopoietic failure. Collectively, our results suggest that the combined deficiency of formaldehyde clearance mechanisms leads to the complex clinical features due to overload of formaldehyde-induced DNA damage, thereby saturation of DNA repair processes.

Late-onset ornithine transcarbamylase deficiency: a rare cause of recurrent abnormal behavior in adults.

BACKGROUND: Ornithine transcarbamylase is an enzyme of the urea cycle, which produces urea from ammonia. Although ornithine transcarbamylase deficiency mainly occurs as a severe neonatal-onset disease, a late-onset form that could become symptomatic from infancy to adulthood is also known. CASE PRESENTATION: A 34-year-old man presented with sudden onset of abnormal behavior, lethargy, and hyperammonemia (108 µmol/L). He had recently increased daily protein intake, which suggested urea cycle disorder. After initiation of protein-restricted diet and treatment with arginine and sodium phenylbutyrate, his symptoms resolved, along with a decrease in the ammonia level. An R40H(c.119G > A) mutation in the OTC gene was identified. CONCLUSION: Awareness of adult onset ornithine transcarbamylase deficiency in a patient with acute psychiatric symptoms due to hyperammonemia is important.

Diabetes mellitus exacerbates citrin deficiency via glucose toxicity.

AIMS: Citrin is an aspartate/glutamate carrier that composes the malate-aspartate reduced nicotinamide adenine dinucleotide (NADH) shuttle in the liver. Citrin deficiency causes neonatal intrahepatic cholestasis (NICCD), failure to thrive and dyslipidemia (FTTDCD) and adult-onset type II citrullinemia (CTLN2). Hepatic glycolysis is essentially impaired in citrin deficiency and a low-carbohydrate diet was recommended. The lethal effect of infusion of glycerol- and fructose-containing osmotic agents was reported in these patients. Hyperalimentation was also reported to exacerbate CTLN2; however, glucose toxicity was unclear in citrin deficiency. METHODS: We studied two CTLN2 patients complicated with type 2 diabetes mellitus (DM), Case 1 presented with hyperammonemic encephalopathy accompanied with DM, while Case 2 presented with hyperammonemic encephalopathy relapse upon the onset of DM after several years' remission following supplementation with medium-chain triglycerides (MCT) and adherence to a low-carbohydrate diet. RESULTS: Insulin therapy with MCT supplementation and a low-carbohydrate diet improved hyperammonemia and liver function in Case 1. Additional insulin therapy improved hyperammonemia in Case 2. CONCLUSION: Glucose is not toxic for citrin deficiency in normoglycemia because glucose uptake and metabolism by hepatocytes are limited in normoglycemia. However, glucose becomes toxic during persistent hyperglycemia and antidiabetic therapy is indispensable for CTLN2 patients with DM.

Cystic biliary atresia with paucity of bile ducts and gene mutation in KDM6A: a case report.

BACKGROUND: Biliary atresia (BA) cases are generally not associated with congenital abnormalities. However, accurate diagnosis of BA is often challenging because the histopathological features of BA overlap with those of other pediatric liver diseases and rarely overlap with those of other genetic disorders. We experienced a rare case of BA with the histopathological finding of bile duct paucity, a gene mutation in KDM6A, and KS-like phenotypes. CASE PRESENTATION: A male baby was diagnosed with biliary atresia by intraoperative cholangiography at 4 days of age, and histological examination following a liver biopsy revealed a paucity of bile ducts and several typical clinical findings of Alagille syndrome. However, Alagille syndrome was ruled out after neither JAG1 nor NOTCH2 gene mutations were identified. Whole-exome sequencing on DNA from his parents was additionally performed to examine other possible syndromic disorders, and a mutation was identified in KDM6A. However, Kabuki syndrome was not diagnosed as a result. The histological finding of interlobular bile duct paucity and the genetic mutation in KDM6A, as well as several clinical findings consistent with Alagille syndrome or Kabuki syndrome, made it difficult to confirm the diagnosis of BA. CONCLUSIONS: Based on the interesting findings of the present case, we hypothesized that KDM6A is associated with hepatic malformations via a connection with the Notch signaling pathway.

[Possible relationship between prescription medications and urinary dysfunction in elderly home health care patients].

AIM: Although urinary incontinence (UI) in the elderly appears to be related to polypharmacy, it is unclear whether multiple medications elevate UI quantitatively or qualitatively. There have been few studies on the association of polypharmacy with each type of UI. The present survey aimed to clarify these issues. METHOD: The subjects were elderly home health care patients ≥65 years of age taking ≥5 prescription medications and not being treated with anti-cancer agent. The visiting nurses filled out a questionnaire based on their nursing and medication records. Types of UI were evaluated according to a UI checklist. RESULTS: A total of 167 subjects (97 women, 70 men, mean age of 83.8 years) were eligible for the data analysis. Subjects talking 5-9 prescription medications accounted for 59.3%, while those talking≥10 counted for 40.7%. Men talking ≥10 medications showed a slight but non-significant increased risk of UI. In women, α-adrenergic antagonists and benzodiazepines significantly increased the risk of stress UI and urge UI, respectively. Furthermore, α-adrenergic antagonists reduced the risk of functional UI, whereas acetylcholinesterase inhibitors elevated it. α-adrenergic antagonists in combination with benzodiazepines also significantly increased the risk of stress UI and urge UI, while α-adrenergic antagonists with acetylcholinesterase inhibitors increased the risk of stress UI. In men, there were no prescription medications that were particularly related to UI. CONCLUSIONS: The present results suggest that there are gender differences in prescription medications-induced UI. It is likely that the causing medications are different depending on the type of UI, and the combination of them significantly increase the risk of UI.

Three Cases of KCNT1 Mutations: Malignant Migrating Partial Seizures in Infancy with Massive Systemic to Pulmonary Collateral Arteries.

KCNT1 mutations are gain-of-function mutations in potassium channels resulting in severe infantile epilepsy. Herein we describe 3 infants with malignant migrating partial seizures with KCNT1 mutations accompanied by massive systemic to pulmonary collateral arteries with life-threatening hemoptysis and heart failure.

Critical role of Yp inversion in PRKX/PRKY-mediated Xp;Yp translocation in a patient with 45,X testicular disorder of sex development.

45,X testicular disorder of sex development (TDSD), previously known as 45,X maleness, with unbalanced Xp;Yp translocation is an extremely rare condition caused by concomitant occurrence of loss of an X chromosome of maternal origin and an aberrant Xp;Yp translocation during paternal meiosis. We identified a Japanese male infant with an apparently 45,X karyotype who exhibited chondrodysplasia punctata and growth failure. Cytogenetic analysis revealed a 45,X.ish der(X)t(X;Y)(p22.33;p11.2)(DXZ1+,SRY+) karyotype. Array comparative genome hybridization analysis showed a simple Xp terminal deletion involving SHOX and ARSE with the breakpoint just centromeric to PRKX, and an apparently complex Yp translocation with the middle Yp breakpoint just telomeric to PRKY and the centromeric and the telomeric Yp breakpoints around the long inverted repeats for the generation of a common paracentric Yp inversion. Subsequently, a long PCR product was obtained with an X-specific and a Y-specific primers that were designed on the assumption of the presence of a Yp inversion that permits the alignment of PRKX and PRKY in the same direction, and the translocation fusion point was determined to reside within a 246 bp X-Y homologous segment at the "hot spot A" in the 5' region of PRKX/PRKY, by sequential direct sequencing for the long PCR product. These results argue not only for the presence of rare 45,X-TDSD with Xp;Yp translocation, but also for a critical role of a common paracentric Yp inversion in the occurrence of PRKX/PRKY-mediated unbalanced Xp;Yp translocation.

MLL2 and KDM6A mutations in patients with Kabuki syndrome.

Kabuki syndrome is a congenital anomaly syndrome characterized by developmental delay, intellectual disability, specific facial features including long palpebral fissures and ectropion of the lateral third of the lower eyelids, prominent digit pads, and skeletal and visceral abnormalities. Mutations in MLL2 and KDM6A cause Kabuki syndrome. We screened 81 individuals with Kabuki syndrome for mutations in these genes by conventional methods (n = 58) and/or targeted resequencing (n = 45) or whole exome sequencing (n = 5). We identified a mutation in MLL2 or KDM6A in 50 (61.7%) and 5 (6.2%) cases, respectively. Thirty-five MLL2 mutations and two KDM6A mutations were novel. Non-protein truncating-type MLL2 mutations were mainly located around functional domains, while truncating-type mutations were scattered through the entire coding region. The facial features of patients in the MLL2 truncating-type mutation group were typical based on those of the 10 originally reported patients with Kabuki syndrome; those of the other groups were less typical. High arched eyebrows, short fifth finger, and hypotonia in infancy were more frequent in the MLL2 mutation group than in the KDM6A mutation group. Short stature and postnatal growth retardation were observed in all individuals with KDM6A mutations, but in only half of the group with MLL2 mutations.

Fatigue and quality of life in citrin deficiency during adaptation and compensation stage.

Citrin-deficient children and adolescents between adult-onset type II citrullinemia and neonatal intrahepatic cholestasis by citrin deficiency do not have clear clinical features except for unusual diet of high-fat, high-protein, and low-carbohydrate food. The aims of the present study are to characterize fatigue and quality of life (QOL) in citrin-deficient patients during adaptation and compensation stage, and to define the relationship between fatigue and QOL. The study subjects were 55 citrin-deficient patients aged 1-22years (29 males) and 54 guardians. Fatigue was evaluated by self-reports and proxy-reports of the PedsQL Multidimensional Fatigue Scale. QOL was evaluated by the PedsQL Generic Core Scales. Both scale scores were significantly lower in child self-reports (p<0.01 and p<0.05, respectively) and parent proxy-reports (p<0.01 and p<0.01, respectively) than those of healthy children. Citrin-deficient patients with scores of 50 percentile or less of healthy children constituted 67.5% of the sample for the Fatigue Scale and 68.4% for the Generic Core Scales. The PedsQL Fatigue Scale correlated with the Generic Core Scales for both the patients (r=0.56) and parents reports (r=0.71). Assessments by the patients and their parents showed moderate agreement. Parents assessed the condition of children more favorably than their children. The study identified severe fatigue and impaired QOL in citrin-deficient patients during the silent period, and that such children perceive worse fatigue and poorer QOL than those estimated by their parents. The results stress the need for active involvement of parents and medical staff in the management of citrin-deficient patients during the silent period.

Homozygous deletion of DIS3L2 exon 9 due to non-allelic homologous recombination between LINE-1s in a Japanese patient with Perlman syndrome.

Perlman syndrome is a rare, autosomal recessive overgrowth disorder. Recently, the deletion of exon 9 and other mutations of the DIS3L2 gene have been reported in patients; however, the mechanism behind this deletion is still unknown. We report the homozygous deletion of exon 9 of DIS3L2 in a Japanese patient with Perlman syndrome. We identified the deletion junction, and implicate a non-allelic homologous recombination (NAHR) between two LINE-1 (L1) elements as the causative mechanism. Furthermore, the deletion junctions were different between the paternal and maternal mutant alleles, suggesting the occurrence of two independent NAHR events in the ancestors of each parent. The data suggest that the region around exon 9 might be a hot spot of L1-mediated NAHR.

Mutation analysis of the SHOC2 gene in Noonan-like syndrome and in hematologic malignancies.

Noonan syndrome is an autosomal dominant disease characterized by dysmorphic features, webbed neck, cardiac anomalies, short stature and cryptorchidism. It shows phenotypic overlap with Costello syndrome and cardio-facio-cutaneous (CFC) syndrome. Noonan syndrome and related disorders are caused by germline mutations in genes encoding molecules in the RAS/MAPK pathway. Recently, a gain-of-function mutation in SHOC2, p.S2G, has been identified as causative for a type of Noonan-like syndrome characterized by the presence of loose anagen hair. In order to understand the contribution of SHOC2 mutations to the clinical manifestations of Noonan syndrome and related disorders, we analyzed SHOC2 in 92 patients with Noonan syndrome and related disorders who did not exhibit PTPN11, KRAS, HRAS, BRAF, MAP2K1/2, SOS1 or RAF1 mutations. We found the previously identified p.S2G mutation in eight of our patients. We developed a rapid detection system to identify the p.S2G mutation using melting curve analysis, which will be a useful tool to screen for the apparently common mutation. All the patients with the p.S2G mutation showed short stature, sparse hair and atopic skin. Six of the mutation-positive patients showed severe mental retardation and easily pluckable hair, and one showed leukocytosis. No SHOC2 mutations were identified in leukemia cells from 82 leukemia patients. These results suggest that clinical manifestations in SHOC2 mutation-positive patients partially overlap with those in patients with typical Noonan or CFC syndrome and show that easily pluckable/loose anagen hair is distinctive in SHOC2 mutation-positive patients.

Various types of LRP5 mutations in four patients with osteoporosis-pseudoglioma syndrome: identification of a 7.2-kb microdeletion using oligonucleotide tiling microarray.

Osteoporosis-pseudoglioma syndrome (OPS; OMIM 259770) is an autosomal-recessive genetic disorder characterized by severe osteoporosis and visual disturbance from childhood. Biallelic mutations in the low-density lipoprotein receptor-related protein 5 gene (LRP5) have been frequently detected, while a subset of patients had only one or no detectable mutation. We report on the clinical and molecular findings of four unrelated Japanese patients with the syndrome. The four patients had typical skeletal and ocular phenotypes of OPS, namely severe juvenile osteoporosis and early-onset visual disturbance, with or without mental retardation. We undertook standard PCR-based sequencing for LRP5 and found four missense mutations (p.L145F, p.T244M, p.P382L, and p.T552M), one nonsense mutation (p.R1534X), and one splice site mutation (c.1584+1G>A) among four OPS patients. Although three patients had two heterozygous mutations, one had only one heterozygous splice site mutation. In this patient, RT-PCR from lymphocytic RNA demonstrated splice error resulting in 63-bp insertion between exons 7 and 8. Furthermore, the patient was found to have only mutated RT-PCR fragment, implying that a seemingly normal allele did not express LRP5 mRNA. We then conducted custom- designed oligonucleotide tiling microarray analyses targeted to a 600-kb genome region harboring LRP5 and discovered a 7.2-kb microdeletion encompassing exons 22 and 23 of LRP5. We found various types of LRP5 mutations, including an exon-level deletion that is undetectable by standard PCR-based mutation screening. Oligonucleotide tiling microarray seems to be a powerful tool in identifying cryptic structural mutations.

Roles of specific cytokines in bone remodeling and hematopoiesis in Gaucher disease.

BACKGROUND: Gaucher disease type 1 and type 3 are characterized by bone disease and hematological symptoms. It is known that monocyte/macrophage lineage is activated in Gaucher disease, and accordingly certain cytokines are elevated in blood. The aim of the present study was to explore the possible relationships between cytokines and bone remodeling and hematological abnormalities in this disease. METHODS: The concentrations of seven cytokines and two related proteins were measured in patients with Gaucher disease type 1 and type 3 (n= 8; age range, 2-50 years) who had received enzyme replacement therapy. RESULTS: Concentrations of interleukin-18 and transforming growth factor-beta1 were elevated in patients of all clinical types. Elevation of these cytokines in Gaucher disease has not been previously reported. Analysis of correlation among cytokines and bone-turnover markers showed that interleukin-18 concentration was correlated with each of two bone formation markers of bone-specific alkaline phosphatase activity and osteocalcin concentration, whereas macrophage colony-stimulating factor concentration correlated with the bone absorption marker of N-telopeptide to helix in urine. Concentrations of macrophage colony-stimulating factor and tumor necrosis factor-alpha were inversely correlated with hemoglobin concentration. CONCLUSIONS: Interleukin-18 and monocyte macrophage colony-stimulating factor are cytokines mainly involved in the mechanism of bone disease, while macrophage colony-stimulating factor and tumor necrosis factor-alpha may play a role in the development of hematological abnormalities in Gaucher disease.

Screening for Alagille syndrome mutations in the JAG1 and NOTCH2 genes using denaturing high-performance liquid chromatography.

Mutations in the JAG1 gene and the NOTCH2 gene cause Alagille syndrome. At present, however, genetic testing of Alagille syndrome is not commonly applied in clinical settings because the currently available assays are technically and financially demanding, mainly because of the size of the genes. In the present study, we optimized the highly sensitive and specific mutation scanning method automated denaturing high-performance liquid chromatography (DHPLC) to analyze the entire coding region of JAG1 and NOTCH2. The coding region was amplified by 69 primer pairs, all of which have the same cycling conditions, aliquoted on a 96-well format PCR plate. In this manner, all the exons were simultaneously amplified using a single block in a thermal cycler. We then wrote a computer script to analyze each segment of JAG1 and NOTCH2 by DHPLC in a serial manner using conditions that were optimized for each amplicon. The implementation of this screening method for JAG1 and NOTCH2 will help medical geneticists confirm their clinical impressions and provide accurate genetic counseling to the patients with Alagille syndrome and their families.