Alagille Syndrome

Clinical Characteristics
Ocular Features: 

The ocular findings in Alagille syndrome are often of little functional significance but can be sufficient to suggest the diagnosis without further study of the systemic features.  Posterior embryotoxon is found in 95% of individuals while iris abnormalities such as ectopic pupils are seen in 45%, abnormal fundus pigmentation is common (hypopigmentation in 57%, diffuse pigment speckling in 33%), and optic disc anomalies have been reported in 76%.  One study found that 90% of individuals have optic disk drusen by ultrasonography.  The anterior chamber anomalies are considered by some to be characteristic of Axenfeld anomaly.  The presence of these ocular findings in children with cholestasis should suggest Alagille syndrome.  Ocular examination of the parents can also be helpful in this autosomal dominant disorder as some of the same changes are present in one parent in more than a third of cases.

Systemic Features: 

A variety of  systemic features, some of them serious malformations, occur in Alagille syndrome.  Among the most common is a partial intrahepatic biliary atresia leading to cholestasis and jaundice.  Skeletal malformations include 'butterfly' vertebrae, shortened digits, short stature, a broad forehead, and a pointed chin.  The tip of the nose may appear bulbous.  These features have suggested to some that there is a characteristic facial dysmorphology.  Vascular malformations are common including aneurysms affecting major vessels, valvular insufficiency, coarctation of the aorta, and stenosis and these are often responsible for the most serious health problems.  In fact, vascular events have been reported to be responsible for mortality in 34% of one cohort.  Chronic renal insufficiency develops in a minority of patients.  This disorder should always be considered in children with cholestasis, especially when accompanied by cystic kidney disease.  Brain MRIs may show diffuse or focal hyperintensity of white matter even in the absence of hepatic encephalopathy.

Genetics

This is an autosomal dominant condition secondary to various mutations in the JAG1 gene located on chromosome 20 (20p12).  Penetrance is nearly 100% but there is considerable variation in expression.  A far less common variant of this disorder, ALGS2 (610205), is caused by a mutation in the NOTCH2 gene (1p13-p11).

Treatment
Treatment Options: 

No cure is available but individual organ disease may be treatable.  The ocular abnormalities generally do not cause vision difficulties.

Reversible of white matter changes has been noted in a single child following liver transplantation.

 

References
Article Title: 

CT-defined phenotype of pulmonary artery

Rodriguez RM, Feinstein JA, Chan FP. CT-defined phenotype of pulmonary artery
stenoses in Alagille syndrome
. Pediatr Radiol. 2016 Apr 4. [Epub ahead of print].

PubMed ID: 
27041277

Alagille syndrome: clinical and ocular pathognomonic features

El-Koofy NM, El-Mahdy R, Fahmy ME, El-Hennawy A, Farag MY, El-Karaksy HM. Alagille syndrome: clinical and ocular pathognomonic features. Eur J Ophthalmol. 2010 Jul 28. pii: 192165A5-8631-4C06-9C47-9AD63688B02A. [Epub ahead of print]

PubMed ID: 
20677167

Ocular abnormalities in Alagille syndrome

Hingorani M, Nischal KK, Davies A, Bentley C, Vivian A, Baker AJ, Mieli-Vergani G, Bird AC, Aclimandos WA. Ocular abnormalities in Alagille syndrome. Ophthalmology. 1999 Feb;106(2):330-7.

PubMed ID: 
9951486

References

Ho DK, Levin AV, Anninger WV, Piccoli DA, Eagle RC Jr. Anterior Chamber Pathology in Alagille Syndrome. Ocul Oncol Pathol. 2016 Oct;2(4):270-275.

PubMedID: 27843908

Rodriguez RM, Feinstein JA, Chan FP. CT-defined phenotype of pulmonary artery
stenoses in Alagille syndrome
. Pediatr Radiol. 2016 Apr 4. [Epub ahead of print].

PubMedID: 27041277

Takenouchi T, Shimozato S, Kosaki K, Momoshima S, Takahashi T. Reversible diffuse white matter lesion in Alagille syndrome. Pediatr Neurol. 2011 Jul;45(1):54-6.

PubMedID: 21723462

El-Koofy NM, El-Mahdy R, Fahmy ME, El-Hennawy A, Farag MY, El-Karaksy HM. Alagille syndrome: clinical and ocular pathognomonic features. Eur J Ophthalmol. 2010 Jul 28. pii: 192165A5-8631-4C06-9C47-9AD63688B02A. [Epub ahead of print]

PubMedID: 20677167

Kamath BM, Loomes KM, Piccoli DA. Medical management of Alagille syndrome. J Pediatr Gastroenterol Nutr. 2010 Jun;50(6):580-6.

PubMedID: 20479679

Kamath BM, Spinner NB, Emerick KM, Chudley AE, Booth C, Piccoli DA, Krantz ID. Vascular anomalies in Alagille syndrome: a significant cause of morbidity and mortality. Circulation. 2004 Mar 23;109(11):1354-8.

PubMedID: 14993126

Hingorani M, Nischal KK, Davies A, Bentley C, Vivian A, Baker AJ, Mieli-Vergani G, Bird AC, Aclimandos WA. Ocular abnormalities in Alagille syndrome. Ophthalmology. 1999 Feb;106(2):330-7.

PubMedID: 9951486