Effect of Kasai procedure on hepatic outcome in Alagille syndrome.

OBJECTIVES: Alagille syndrome (AGS) frequently presents with neonatal jaundice and can mimic other causes of high gamma-glutamyl transpeptidase (GGT) cholestasis, most notably biliary atresia. As a result infants with AGS may undergo intraoperative cholangiogram and even Kasai procedure. The aim of the study was to assess the hepatic outcomes of children with AGS who underwent the Kasai procedure. PATIENTS AND METHODS: A retrospective review of the AGS clinical database at the Children's Hospital of Philadelphia was performed to identify clinically defined patients with AGS who underwent a Kasai. A cohort of Alagille control subjects was selected with equivalent symptoms of neonatal jaundice and matched for age and presence of cardiac anomaly. JAGGED1-mutation analysis was performed on available samples. Clinical courses were reviewed. Fisher exact and t tests were used for analysis. RESULTS: Of the 430 patients with AGS, 19 underwent a Kasai procedure (K). The control cohort (C) consisted of 36 patients. Total bilirubin measured between 6 and 10 weeks of age in each cohort was equivalent (K: 9.6 mg/dL, C: 8.7 mg/dL); GGT levels were higher in the control group (K:493.4 U/L, C:574.4 U/L). Of note, the Kasai cohort had a significantly larger number of liver transplants (K: 9 [47.3%], C: 5 [13.9%], P = 0.01) and sustained higher mortality (K: 6 [31.6%], C: 1 [2.8%], P = 0.005). There was no genotype-phenotype correlation between the mutations identified and patients who underwent Kasai. CONCLUSIONS: These data suggest that the Kasai procedure, although appropriate for children with biliary atresia, does not benefit children with AGS and actually appears to worsen outcome. The current data suggest that the Kasai is not a marker for underlying severe liver disease, but the procedure itself may have a detrimental effect on outcome. An appropriate medical evaluation and particular consideration of AGS is essential before surgical referral in infants with high GGT cholestasis.

Pathologic lower extremity fractures in children with Alagille syndrome.

OBJECTIVES: : In this retrospective study, we aimed to determine the incidence and distribution of fractures in patients with Alagille syndrome, 1 of the leading inherited causes of pediatric cholestatic liver disease. MATERIALS AND METHODS: : Surveys regarding growth, nutrition, and organ involvement were distributed to patient families in the Alagille Syndrome Alliance of the Children's Hospital of Philadelphia research database. Patients with a history of fracture were identified by their response to 1 question, and details characterizing each patient's medical, growth, and fracture history were obtained through chart review and telephone contact. RESULTS: : Twelve of 42 patients (28%) reported a total of 27 fractures. Patients experienced fractures at a mean age of 5 years, which contrasts with healthy children, in whom fracture incidence peaks in adolescence. Fractures occurred primarily in the lower extremity long bones (70%) and with little or no trauma (84%). Estimated incidence rate calculations yielded 399.6 total fractures per 10,000 person-years (95% confidence interval 206.5, 698.0) and 127.6 femur fractures per 10,000 person-years (95% confidence interval 42.4, 297.7). There were no differences in sex, age distribution, or organ system involvement between the fracture and no-fracture groups. CONCLUSIONS: : Children with Alagille syndrome may be at risk for pathologic fractures, which manifest at an early age and in a unique distribution favoring the lower extremity long bones. Although this preliminary study is limited by small sample size and potential ascertainment bias, the data suggest that larger studies are warranted to further characterize fracture risk and explore factors contributing to bone fragility in these children.

A longitudinal study to identify laboratory predictors of liver disease outcome in Alagille syndrome.

OBJECTIVES: Liver disease in Alagille syndrome (AGS) is highly variable, ranging from biochemical abnormalities only to end-stage disease. It is not possible to predict whether a child with cholestasis will have improvement or progression of liver disease. This poses a challenge to the clinician in terms of timing therapies. The study aim was to identify laboratory markers present in children younger than 5 years that could predict the ultimate outcome of liver disease in AGS. METHODS: A retrospective review of laboratory data from 33 subjects with AGS was performed. Patients older than 10 years of age were stratified into mild (22) and severe (11) hepatic outcome groups. Nonparametric analysis was performed on longitudinal data from birth to 5 years to determine association with hepatic outcome. JAGGED1 mutational analysis was performed on available samples. RESULTS: The following variables were statistically different between severe and mild outcome groups: total bilirubin (TB, P = 0.0001), conjugated bilirubin (CB, P = 0.0066), and cholesterol (P = 0.0022). Further analysis revealed cutoff values that differentiated between severe and mild outcomes; TB 6.5 mg/dL (111 micromol/L), CB 4.5 mg/dL (77 micromol/L), and cholesterol 520 mg/dL (13.5 mmol/L). Genetic analysis of JAGGED1 mutations did not reveal genotype-phenotype correlation. CONCLUSIONS: TB >6.5 mg/dL, CB >4.5 mg/dL, and cholesterol >520 mg/dL in children younger than 5 years of age are likely to be associated with severe liver disease in later life. These data represent cutoff values below which a child is likely to have a benign outcome and above which more aggressive therapy may be warranted, and can thus be used to guide management.

SNP array mapping of chromosome 20p deletions: genotypes, phenotypes, and copy number variation.

The use of array technology to define chromosome deletions and duplications is bringing us closer to establishing a genotype/phenotype map of genomic copy number alterations. We studied 21 patients and five relatives with deletions of the short arm of chromosome 20 using the Illumina HumanHap550 SNP array to: 1) more accurately determine the deletion sizes; 2) identify and compare breakpoints; 3) establish genotype/phenotype correlations; and 4) investigate the use of the HumanHap550 platform for analysis of chromosome deletions. Deletions ranged from 95 kb to 14.62 Mb, and all of the breakpoints were unique. Eleven patients had deletions between 95 kb and 4 Mb and these individuals had normal development, with no anomalies outside of those associated with Alagille syndrome (AGS). The proximal and distal boundaries of these 11 deletions constitute a 5.4-Mb region, and we propose that haploinsufficiency for only 1 of the 12 genes in this region causes phenotypic abnormalities. This defines the JAG1-associated critical region, in which deletions do not confer findings other than those associated with AGS. The other 10 patients had deletions between 3.28 Mb and 14.62 Mb, which extended outside the critical region, and, notably, all of these patients had developmental delay. This group had other findings such as autism, scoliosis, and bifid uvula. We identified 47 additional polymorphic genome-wide copy number variants (>20 SNPs), with 0 to 5 variants called per patient. Deletions of the short arm of chromosome 20 are associated with relatively mild and limited clinical anomalies. The use of SNP arrays provides accurate high-resolution definition of genomic abnormalities.