[Clinical phenotypes and genotypic spectrum of cystic fibrosis with pancreatic insufficiency in children].

Objective: To investigate the clinical phenotypes and genotypic spectrum of exocrine pancreatic insufficiency in children with cystic fibrosis. Methods: This was a retrospective analysis of 12 children with cystic fibrosis who presented to Children's Hospital of Fudan University from December 2017 to December 2021. Clinical features, fecal elastase-1 level, genotype, diagnosis and treatment were systematically reviewed. Results: A total of 12 children, 7 males and 5 females, diagnosis aged 5.4 (2.0, 10.6) years, were recruited. Common clinical features included chronic cough in 12 cases, malnutrition in 7 cases, steatorrhea in 7 cases, bronchiectasis in 5 cases and electrolyte disturbance in 4 cases. Exocrine pancreatic insufficiency were diagnosed in 8 cases,the main clinical manifestations were steatorrhea in 7 cases, of which 5 cases started in infancy; 6 cases were complicated with malnutrition, including mild in 1 case, moderate in 2 cases and severe in 3 cases; 3 cases had abdominal distension; 2 cases had intermittent abdominal pain; 4 cases showed fatty infiltration or atrophy of pancreas and 3 cases showed no obvious abnormality by pancreatic magnetic resonance imaging or B-ultrasound. All 8 children were given pancreatic enzyme replacement therapy, follow-up visit of 2.3 (1.2,3.2) years. Diarrhea significantly improved in 6 cases, and 1 case was added omeprazole due to poor efficacy. A total of 20 variations of CFTR were detected in this study, of which 7 were novel (c.1373G>A,c.1810A>C,c.270delA,c.2475_2478dupCGAA,c.2489_c.2490insA, c.884delT and exon 1 deletion). Conclusions: There is a high proportion of exocrine pancreatic insufficiency in Chinese patients with cystic fibrosis. The main clinical manifestations are steatorrhea and malnutrition. Steatorrhea has often started from infancy. Pancreatic enzyme replacement therapy can significantly improve the symptoms of diarrhea and malnutrition.

Biallelic deletion in a minimal CAPN15 intron in siblings with a recognizable syndrome of congenital malformations and developmental delay.

Calpainopathies constitute a heterogeneous group of disorders resulting from deficiencies in calpains, calcium-specific proteases that modulate substrates by limited proteolysis. Clinical manifestations depend on tissue-specific expression of the defective calpain and substrate specificity. CAPN15, encoding the Drosophila small optic lobes (sol) homolog, was recently found to cause various eye defects in individuals carrying bi-allelic missense variants. Here we report on two siblings with manifestations reminiscent of Johanson-Blizzard syndrome including failure to thrive, microcephaly, global developmental delay, dysmorphic features, endocrine abnormalities and congenital malformations, in addition to eye abnormalities. Exome sequencing identified a homozygous 47 base-pair deletion in a minimal intron of CAPN15, including the splice donor site. Sequencing of cDNA revealed single exon skipping, resulting in an out-of-frame deletion with a predicted premature termination codon. These findings expand the phenotypic spectrum associated with CAPN15 variants, and suggest that complete loss-of-function is associated with a recognizable syndrome of congenital malformations and developmental delay, overlapping Johanson-Blizzard syndrome and the recently observed brain defects in Capn15 knockout (KO) mice. Moreover, the data highlight the unique opportunity for indel detection in minimal introns.

Increased hydrophilic plasma bile acids are correlated with protection from adiposity in skin-specific stearoyl-CoA desaturase-1 deficient mice.

Stearoyl-CoA desaturase 1 (SCD1) catalyzes the rate limiting step in monounsaturated fatty acid synthesis by inserting a double bond at the delta-9 position of long-chain fatty acids. SCD1 converts stearate (18:0) to oleate (18:1n9) and palmitate (16:0) to palmitoleate (16:1n7), respectively. Mice with global and skin-specific deletion (SKO) of SCD1 exhibit increased whole body energy expenditure and protection against diet-induced adiposity, hepatic steatosis, insulin sensitivity and glucose intolerance. The mechanisms that link cutaneous lipid homeostasis with whole body energy balance are presently unknown. In this study, we reveal that SKO mice demonstrate increased skin surface free cholesterol, decreased circulating total cholesterol and increased taurine-conjugated and hydrophilic bile acids. Tauro-ß-muricholic acid, which is a marker of extrahepatic bile acid synthesis, is significantly elevated in SKO plasma. Bile acid signaling through the bile acid-specific receptor TGR5 is known to be protective against obesity and metabolic disease; a phenotype that is similar to SKO mice. We therefore examined TGR5 expression and its downstream mediator, DIO2, in various tissues and found that both TGR5 and DIO2 expression were significantly increased in brown adipose tissue. In sum, we suggest that skin-derived bile acids are involved in the lean and metabolically healthy phenotype of SKO mice.

Organic solute transporter-ß (SLC51B) deficiency in two brothers with congenital diarrhea and features of cholestasis.

Primary bile acid malabsorption is associated with congenital diarrhea, steatorrhea, and a block in the intestinal return of bile acids in the enterohepatic circulation. Mutations in the ileal apical sodium-dependent bile acid transporter (ASBT; SLC10A2) can cause primary bile acid malabsorption but do not appear to account for most familial cases. Another major transporter involved in the intestinal reclamation of bile acids is the heteromeric organic solute transporter alpha-beta (OSTα-OSTß; SLC51A-SLC51B), which exports bile acid across the basolateral membrane. Here we report the first patients with OSTß deficiency, clinically characterized by chronic diarrhea, severe fat soluble vitamin deficiency, and features of cholestatic liver disease including elevated serum gamma-glutamyltransferase activity. Whole exome sequencing revealed a homozygous single nucleotide deletion in codon 27 of SLC51B, resulting in a frameshift and premature termination at codon 50. Functional studies in transfected cells showed that the SLC51B mutation resulted in markedly reduced taurocholic acid uptake activity and reduced expression of the OSTα partner protein. CONCLUSION: The findings identify OSTß deficiency as a cause of congenital chronic diarrhea with features of cholestatic liver disease. These studies underscore OSTα-OSTß's key role in the enterohepatic circulation of bile acids in humans. (Hepatology 2017).

Dysgenesis of enteroendocrine cells in Aristaless-Related Homeobox polyalanine expansion mutations.

OBJECTIVES: Severe congenital diarrhea occurs in approximately half of patients with Aristaless-Related Homeobox (ARX) null mutations. The cause of this diarrhea is unknown. In a mouse model of intestinal Arx deficiency, the prevalence of a subset of enteroendocrine cells is altered, leading to diarrhea. Because polyalanine expansions within the ARX protein are the most common mutations found in ARX-related disorders, we sought to characterize the enteroendocrine population in human tissue of an ARX mutation and in a mouse model of the corresponding polyalanine expansion (Arx). METHODS: Immunohistochemistry and quantitative real-time polymerase chain reaction were the primary modalities used to characterize the enteroendocrine populations. Daily weights were determined for the growth curves, and Oil-Red-O staining on stool and tissue identified neutral fats. RESULTS: An expansion of 7 alanines in the first polyalanine tract of both human ARX and mouse Arx altered enteroendocrine differentiation. In human tissue, cholecystokinin, glucagon-like peptide 1, and somatostatin populations were reduced, whereas the chromogranin A population was unchanged. In the mouse model, cholecystokinin and glucagon-like peptide 1 populations were also lost, although the somatostatin-expressing population was increased. The ARX protein was present in human tissue, whereas the Arx protein was degraded in the mouse intestine. CONCLUSIONS: ARX/Arx is required for the specification of a subset of enteroendocrine cells in both humans and mice. Owing to protein degradation, the Arx mouse recapitulates findings of the intestinal Arx null model, but is not able to further the study of the differential effects of the ARX protein on its transcriptional targets in the intestine.

Chylomicron retention disease: report of two cases from a Greek Island.

Chylomicron retention disease (CRD), or Anderson disease, is a rare, hereditary cause of fat malabsorption. It is one of the familial hypocholesterolaemia syndromes, along with homozygous hypobetalipoproteinaemia (HBL) and abetalipoproteinaemia (ABL). We report clinical, laboratory and histological data as well as molecular DNA analysis in the case of a 4-month-old boy with failure to thrive and steatorrhea who was diagnosed with CRD. His mother's first cousin, who was diagnosed as hypobetalipoproteinaemia 30 years ago, was also reviewed and his diagnosis was revised to CRD. Both patients were treated with a low fat diet and supplementation with fat-soluble vitamins resulting in significant improvement. In conclusion, CRD is a well-defined cause of fat malabsorption and can be distinguished from other forms of familial hypocholesterolaemia because of its specific lipid profile.

Anderson's disease/chylomicron retention disease in a Japanese patient with uniparental disomy 7 and a normal SAR1B gene protein coding sequence.

BACKGROUND: Anderson's Disease (AD)/Chylomicron Retention Disease (CMRD) is a rare hereditary hypocholesterolemic disorder characterized by a malabsorption syndrome with steatorrhea, failure to thrive and the absence of chylomicrons and apolipoprotein B48 post-prandially. All patients studied to date exhibit a mutation in the SAR1B gene, which codes for an essential component of the vesicular coat protein complex II (COPII) necessary for endoplasmic reticulum to Golgi transport. We describe here a patient with AD/CMRD, a normal SAR1B gene protein coding sequence and maternal uniparental disomy of chromosome 7 (matUPD7). METHODS AND RESULTS: The patient, one of two siblings of a Japanese family, had diarrhea and steatorrhea beginning at five months of age. There was a white duodenal mucosa upon endoscopy. Light and electron microscopy showed that the intestinal villi were normal but that they had lipid laden enterocytes containing accumulations of lipid droplets in the cytoplasm and lipoprotein-size particles in membrane bound structures. Although there were decreased amounts in plasma of total- and low-density lipoprotein cholesterol, apolipoproteins AI and B and vitamin E levels, the triglycerides were normal, typical of AD/CMRD. The presence of low density lipoproteins and apolipoprotein B in the plasma, although in decreased amounts, ruled out abetalipoproteinemia. The parents were asymptomatic with normal plasma cholesterol levels suggesting a recessive disorder and ruling out familial hypobetalipoproteinemia. Sequencing of genomic DNA showed that the 8 exons of the SAR1B gene were normal. Whole genome SNP analysis and karyotyping revealed matUPD7 with a normal karyotype. In contrast to other cases of AD/CMRD which have shown catch-up growth following vitamin supplementation and a fat restricted diet, our patient exhibits continued growth delay and other aspects of the matUPD7 and Silver-Russell Syndrome phenotypes. CONCLUSIONS: This patient with AD/CMRD has a normal SAR1B gene protein coding sequence which suggests that factors other than the SAR1B protein may be crucial for chylomicron secretion. Further, this patient exhibits matUPD7 with regions of homozygosity which might be useful for elucidating the molecular basis of the defect(s) in this individual. The results provide novel insights into the relation between phenotype and genotype in these diseases and for the mechanisms of secretion in the intestine.

Variable phenotypic expression of chylomicron retention disease in a kindred carrying a mutation of the Sara2 gene.

Chylomicron retention disease is a recessive inherited disorder characterized by fat malabsorption and steatorrhea and is associated with failure to thrive in infancy. We describe a kindred carrying a mutation of Sara2 gene causing a chylomicron retention phenotype. The proband was a 5-month-old baby, born of consanguineous, apparently healthy parents from Morocco, with failure to thrive. There was a large quantity of fats in feces and malabsorption of fat-soluble vitamins. Intestinal biopsies showed a diffused enterocyte vacuolization with large cytosolic lipid droplets. Chylomicron retention disease or Anderson disease was hypothesized, and the Sara2 gene was analyzed by direct sequencing. Analysis of the Sara2 gene in the proband identified a 2-nucleotide homozygous deletion in exon 3 leading to a premature stop codon (c.75-76 del TG-L28fsX34). The father was heterozygous for the same mutation, whereas the proband's mother was homozygous, suggesting a variable phenotypic expression of the molecular defect. More studies are needed to understand the reasons of the phenotypic variability of the same molecular defect in the same family.

Chylomicron retention disease: a long term study of two cohorts.

Lipoprotein assembly is critical for the intestinal absorption of dietary lipids and of fat-soluble vitamins. Through their inhibition of chylomicron secretion, mutations of the Sar1B gene coding for Sar1 GTPase are associated with chylomicron retention disease (CRD). The aim of this study was to describe the phenotypic expression of CRD in two clinically and genetically well characterized cohorts, and to compare their long term evolution. The study in 7 children from France (X age 11.3+/-1.7 years) and 9 from Quebec, Canada (X age 12+/-2.5 years) involved data collection from medical records for growth evaluation, neurological and ophthalmological status as well as bone density over an average follow-up period of 4.9 years for the French cohort and of 10.6 years for the Canadian one. All CRD patients presented within the first few months of life with diarrhea and failure to thrive. Severe hypocholesterolemia coupled with normal triglycerides was associated with low LDL and HDL-cholesterol, as well as with low apolipoproteins A-I and B. Varying degrees of essential fatty acid and of vitamin E deficiency were observed. The earlier diagnosis in the Canadian cohort (1.3+/-0.04 years) than in the French one (6.3+/-1.3 years) was unrelated with the severity of presenting symptoms. The fact that the disease had more impact on growth and bone density in the latter group may be related to delayed diagnosis of the disease. Vitamin E deficiency led to functional neurological and ophthalmic changes in a small number of patients but only one developed areflexia. Finally, genotype-phenotype correlation is not obvious in our cohort with CRD; even if, the Canadian subjects with the allele 409G>A had a more severe degree (P<0.001) of hypocholesterolemia than the other patients, many clinical data are inconsistent with a hypothetical genotype-phenotype correlation. This study provides new insights on the phenotypic expression of CRD over time and emphasizes the need to screen the lipid profile of infants with chronic diarrhea and failure to thrive.

Lipoprotein lipase mutation S447X associated with pancreatic calcification and steatorrhea in hyperlipidemic pancreatitis.

BACKGROUND: The factors that whether and how genes involving lipid metabolism including lipoprotein lipase (LPL) and apolipoprotein CII (apo CII) influence occurrence of acute attack of pancreatitis and chronic pancreatitis is not clear. GOALS: The aim of this study was to determine the association of LPL and apo CII genes with acute attack of pancreatitis and chronic pancreatitis in patients with hyperlipidemic pancreatitis (HLP) and hypertriglyceridemia (HTG). STUDY: We performed genetic analysis of 134 patients in Taiwan with HTG (53 with HLP and 81 without HLP). The entire coding and intronic regions of the LPL and apo CII genes were identified with heteroduplex analytical techniques or high resolution melting analysis. All mutations were confirmed by sequencing analysis. Correlation of phenotype and genotype was also analyzed. RESULTS: The frequency of LPL gene mutation rates in HLP patients (17.0%, 9 of 53) was significantly higher than that without HLP attack (4.9%, 4 of 81) (P<0.0001). A total of 10.4% (14 of 134) of our HTG patients carried LPL or apo CII mutation. The most common LPL gene mutation was S447X. There is a high prevalence (77.8%) of HLP attack in HTG patients carrying S447X mutation. Multivariate analysis in HLP patients indicated that the presence of LPL mutation and episode of acute attack were independent risks for pancreatic calcification and steatorrhea. CONCLUSIONS: This is the first complete genetic study analyzing the association of LPL and apo CII mutation in a HLP population. LPL S447X mutation is associated with a higher risk of pancreatic calcification and steatorrhea than those previously known factors in HLP patients.

Phenotypic and genetic characterization of patients with features of "nonclassic" forms of cystic fibrosis.

OBJECTIVE: To determine which features of incomplete or "nonclassic" forms of cystic fibrosis (CF) are associated with deleterious CF transmembrane conductance regulator gene ( CFTR ) mutations, and to explore other etiologies for features not associated with deleterious CFTR mutations. STUDY DESIGN: Clinical features were compared between 57 patients with deleterious mutations in each CFTR and 63 with no deleterious mutations. The Shwachman Bodian Diamond syndrome gene ( SBDS ) was sequenced to search for mutations in patients with no deleterious CFTR mutations and steatorrhea to determine if any had unrecognized Shwachman-Diamond syndrome (SDS). RESULTS: The presence of a common CF-causing mutation, absence of the vas deferens, and Pseudomona aeruginosa in the sputum correlated with the presence of two deleterious CFTR mutations, whereas sweat chloride concentration, diagnostic criteria for CF, and steatorrhea did not. However, sweat chloride concentration correlated with CFTR mutation status in patients infected with P aeruginosa. One patient had disease-causing mutations in each SBDS . CONCLUSIONS: Presence of a common CF-causing mutation, absence of the vas deferens and/or P aeruginosa infection in a patient with features of nonclassic CF are predictive of deleterious mutations in each CFTR , whereas steatorrhea in the same context is likely to have etiologies other than CF transmembrane conductance regulator (CFTR) dysfunction.