Alagille Syndrome Diagnosis

The diagnosis is primarily clinical .Sequence analysis of JAG1 detects mutation in 90% of individuals with symptoms. Around 7% of affected individuals have microdeletion of 20p12. Mutations in NOTCH2 is found in less than 1%. If family-specific mutation is known, molecular genetic testing is offered to first-degree relatives. Prenatal testing for pregnancies at increased risk is possible if the JAG1 or NOTCH2 disease-causing mutation in an affected family member is known. Prenatal testing cannot predict the occurrence or severity of clinical manifestations.

The severity of the disorder can vary within the same family, with symptoms ranging from so mild as to go unnoticed to severe heart and/or liver disease requiring transplantation. The major clinical feature is due to cholestasis, due to bile duct paucity as seen on liver biopsy. Congenital heart defect, mostly pulmonary stenosis, typical facial features, skeletal features and posterior embryotoxon in the eye are commonly found. Renal and central nervous system abnormalities may occur.

History and Symptoms

Itching

Physical Examination

Head, Eyes, Ears, Nose, Throat

A broad, prominent forehead, deep-set eyes, and a small pointed chin may be present. The sensitivity of facies identification to diagnose Alagille syndrome was 76%, the specificity 82%, the positive predictive value 81%, and the negative predictive value 77%. These results suggest that the facies seen in Alagille syndrome is specific to this condition and its recognition is a valuable tool in diagnosis ^[1].
Scleral icterus

Skin

Extremities

Supernumerary digital flexion creases have been identified in one third of patients. Other digital abnormalities include short distal phalanges and fifth finger clinodactyly. Normally, supernumerary digital creases have been reported in less than 1% of the general population.

Lab Studies

Biochemical Evaluation

Total Bilirubin >6.5 mg/dL, Conjugated Bilirubin >4.5 mg/dL, and cholesterol >520 mg/dL in children younger than 5 years of age are likely be associated with severe liver disease in later life ^[2].

Liver Biopsy

A liver biopsy may indicate too few bile ducts (bile duct paucity).

X ray

An unusual butterfly shape of the bones of the spinal column that can be seen in an x-ray

References

↑ Kamath BM, Loomes KM, Oakey RJ, Emerick KE, Conversano T, Spinner NB; et al. (2002). "Facial features in Alagille syndrome: specific or cholestasis facies?". Am J Med Genet. 112 (2): 163–70. doi:10.1002/ajmg.10579. PMID 12244550.
↑ Kamath BM, Munoz PS, Bab N, Baker A, Chen Z, Spinner NB; et al. (2010). "A longitudinal study to identify laboratory predictors of liver disease outcome in Alagille syndrome". J Pediatr Gastroenterol Nutr. 50 (5): 526–30. doi:10.1097/MPG.0b013e3181cea48d. PMC 2861305. PMID 20421762.

[pmid12244550-1] Kamath BM, Loomes KM, Oakey RJ, Emerick KE, Conversano T, Spinner NB; et al. (2002). "Facial features in Alagille syndrome: specific or cholestasis facies?". Am J Med Genet. 112 (2): 163–70. doi:10.1002/ajmg.10579. PMID 12244550.

[pmid20421762-2] Kamath BM, Munoz PS, Bab N, Baker A, Chen Z, Spinner NB; et al. (2010). "A longitudinal study to identify laboratory predictors of liver disease outcome in Alagille syndrome". J Pediatr Gastroenterol Nutr. 50 (5): 526–30. doi:10.1097/MPG.0b013e3181cea48d. PMC 2861305. PMID 20421762.

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