Heimler syndrome explained

Heimler syndrome
Synonyms:	Deafness-enamel hypoplasia-nail defects syndrome
Causes:	Mutations in the PEX1 or PEX6 genes

Heimler syndrome is a rare autosomal recessive condition characterized by sensorineural hearing loss, amelogenesis imperfecta, nail abnormalities and occasional or late-onset retinal pigmentation

Signs/symptoms

This condition is characterised by sensorineural hearing loss, enamel hypoplasia of the secondary dentition, nail abnormalities and occasional or late-onset retinal pigmentation abnormalities.

Genetics

This condition is caused by mutations in peroxisomal biogenesis factor 1 (PEX1) or peroxisomal biogenesis factor 6 (PEX6) genes.^[1] These gene are involved in peroxisome biogenesis. PEX 1 is located on long arm of chromosome 7 (7q21).2 PEX 6 is located on the short arm of chromosome 6 (6p21). These genes encode AAA+ ATPases. They form part of the mechanism that shuttles the peroxisome targeting signal receptor protein PEX5 back to the cytosol after release of its protein cargo within the peroxisomal lumen.

Diagnosis

The diagnosis is made on clinical grounds and confirmed by gene sequencing.

Treatment

There is no treatment for this condition known at present.

Prognosis

This condition tends to produce only mild abnormalities. Life expectancy is normal.

Epidemiology

This is rare disorder. Precise estimates of its prevalence are not known but it appears be to be < 1/10⁶

History

This condition was first described in 1991.^[2]

Notes and References

Ratbi I, Falkenberg KD, Sommen M, Al-Sheqaih N, Guaoua S, Vandeweyer G, Urquhart JE, Chandler KE, Williams SG, Roberts NA, El Alloussi M, Black GC, Ferdinandusse S, Ramdi H, Heimler A, Fryer A, Lynch SA, Cooper N, Ong KR, Smith CE, Inglehearn CF, Mighell AJ, Elcock C, Poulter JA, Tischkowitz M, Davies SJ, Sefiani A, Mironov AA, Newman WG, Waterham HR, Van Camp G (2015) Heimler syndrome is caused by hypomorphic mutations in the peroxisome-biogenesis genes PEX1 and PEX6. Am J Hum Genet 97(4):535-545
Heimler A, Fox JE, Hershey JE, Crespi P: Sensorineural hearing loss, enamel hypoplasia, and nail abnormalities in sibs. Am J Med Genet 39: 192–195