NEPHRONOPHTHISIS AND EXTRARENAL SYMPTOMS

 

NPH phenotypically presents either as isolated renal disease or as a complex syndrome with manifestation in multiple organs. Most often affected organs are the eyes, liver, skeleton or the central nervous system:

Ophthalmological phenotype:

The eyes are most frequently affected in NPH. A rough distinction in two different ways of affection is made: the impairment of ocular movements (oculomotor apraxia e.g. Cogan) and disorders of the retina (retinitis pigmentosa e.g. Senior – Løken Syndrome). The severe congenital form of retinitis pigmentosa (Leber’s congenital amaurosis) is associated with congenital blindness, nystagmus and pupils unresponsive to light. Retinitis pigmentosa has a later onset, first manifests with night blindness and has a slow progress of visual impairment.

Central nervous system:

Different neurological abnormalities can be associated with NPH including oculomotor apraxia, cerebellar hypoplasia, muscular hypotension, seizures, encephalocele, delay of speech development and cognitive impairment.

Skeleton:

Polydactyly, short finger and thoracic deformation are for instance common in Jeune asphyxiating thoracic dysplasia. Cone shaped epiphysis are characteristic for Mainzer – Saldino syndrome. Different other skeletal abnormalities can be associated with NPH and are summarized as ciliary chondrodysplasic syndromes.

Liver:

Congenital liver fibrosis can be found in different ciliopathies (e.g. Boichis syndrome, Arima syndrome, Meckel – Gruber syndrome) and can be isolated or associated with NPH and abnormalities in other organs.

Situs inversus and congenital heart defects:

Situs inversus and congenital heart defects (especially atrial septal defect) are most common in infantile NPH but can also be found in other ciliopathies.

NPH can appear as a renal manifestation of clearly defined syndromes summarized as NPH related ciliopathies (NPH – RC). The following picture shows the most important syndromes:

Nephronophthisis and extrarenal symptoms - summary

 

Eyes retinitis pigmentosa Senior-Løken syndrome
Bardet-Biedl syndrome
Arima syndrome (cerebro-oculo-hepato-renal syndrome)
Alstrom syndrome
RHYNS syndrome
oculomotor apraxia Cogan syndrome
nystagmus Joubert syndrome and associated disease
coloboma COACH syndrome
CNS encephalocele Meckel – Gruber syndrome
aplasia of the vermis Joubert syndrome and associated diseases
hypopituitarism RHYNS syndrome
Liver hepatic fibrosis Boichis syndrome
Meckel – Gruber syndrome
Arima syndrome
Joubert syndrome and associated diseases
Skeleton short ribs Jeune asphyxiatign thoracic dysplasia
cone shaped epiphyses Mainzer – Saldino syndrome
polydaktyly Joubert syndrome and associated diseases
Bardet – Biedl syndrome
Ellis-van-Creveld syndrome
other skeletal abnormalities Cranioectodermale dysplasia/ Sensenbrenner syndrome
Ellis-van-Creveld syndrome
other defects: situs inversus, congenital heart defect

sources
  • Wolf M. Nephronophthisis and related syndromes. Curr Opin Pediatr. 2015 Apr; 27(2): 201–211.
  • Huber C, Cormier-Daire V. Ciliary disorder of the skeleton. Am J Med Genet C Semin Med Genet. 2012;160C:165–74.
  • Otto EA, Schermer B, Obara T, et al. Mutations in INVS encoding inversin cause nephronophthisis type 2, linking renal cystic disease to the function of primary cilia and left-right axis determination. Nat Genet. 2003;34:413–420.