Table 2.

Disorders to Consider in the Differential Diagnosis of PAX2-Related Disorder

Diff Dx DisorderGene(s)/
MOIClinical Features of DiffDx Disorder
KidneyEyeDistingishing from PAX2-related disorder
CHARGE syndrome 1CHD7 2ADOccasional finding: renal anomalies incl dysgenesis, horseshoe/ectopic kidneyUnilateral or bilateral coloboma of the iris, retina-choroid, &/or disc w/or w/o microphthalmosCraniofacial findings incl cleft lip/palate or choanal atresia; may be assoc w/iris coloboma or retinal coloboma
Branchiootorenal syndrome EYA1 3
ADOligomeganephronia, renal malformations ranging from mild renal hypoplasia to bilateral renal agenesis, → ESRD later in life in someLacrimal duct aplasia; gustatory lacrimationAssoc w/outer-ear malformations; may be assoc w/inner-ear abnormalities incl enlarged vestibular aqueduct & severe sensorineural or mixed hearing loss
Cat-eye syndrome (OMIM 115470)Tetraploid dosage of proximal 22qADKidney abnormalitiesColobomatous eye defectsIris coloboma
PAX6 pathogenic variants
(See Aniridia.)
PAX6 4ADNo kidney findings reportedComplete or partial iris hypoplasia usually (not always) w/assoc foveal hypoplasia → ↓ visual acuity & nystagmus presenting in early infancyNote: No clinical overlap between aniridia & PAX2-related disorder; frequently confused as both involve mutation of a PAX gene expressed in the eye
Joubert syndrome and related disorders (JSRD)>30 genesAR 5
Renal disease in someRetinal dystrophy &optic nerve colobomas in someIncl developmental delay & hepatic & cerebellar defects (not typical of PAX2-related disorder); see footnote 6 for clinical features of JSRD.
Congenital anomalies of the kidney and urinary tract (CAKUT) 7>20 genesAD
Renal hypodysplasia / agenesis, vesico-urerteral reflux, cystic dysplasia, ureteropelvic junction obstruction, & other urinary tract abnormalitiesNoneAnomalies confined to the kidney & renal tract

AD = autosomal dominant; AR = autosomal recessive; DiffDx = differential diagnosis; MOI = mode of inheritance; XL = X-linked


Coloboma, heart malformations, atresia choanae, restriction of growth and development, genital abnormalities, ear and hearing defects syndrome


An estimated 65%-70% of individuals with CHARGE syndrome have pathogenic variants in or deletions of CHD7. Pathogenic variants in PAX2 were not identified in a small series of persons with CHARGE syndrome [Tellier et al 2000; Schimmenti, unpublished].


Joubert syndrome is inherited predominantly in an autosomal recessive manner. OFD1-related JS is inherited in an X-linked manner.


Joubert syndrome is characterized by a distinctive cerebellar and brain stem malformation (the "molar tooth sign" seen on cranial MRI), hypotonia, developmental delays, and either episodic hyperpnea (or apnea) or atypical eye movements, or both. Most children with Joubert syndrome develop truncal ataxia.


From: PAX2-Related Disorder

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