Congenital Hypotrichosis with Juvenile Macular Dystrophy
|Disease group||Ectodermal Dysplasia|
|DISEASE NAME||CONGENITAL HYPOTRICHOSIS WITH JUVENILE MACULAR DYSTROPHY|
|Synonymous||HJMD, Hypotrichosis with cone-rod dystrophy|
|Gene (s)||CDH3 (114021)|
Congenital hypotrichosis with juvenile macular dystrophy (HJMD) is a rare autosomal recessive syndrome first reported by Wagner in 1935. Characteristic features comprise hair loss and progressive macular degeneration leading to reduced visual acuity and early blindness. EEM (ectodermal dysplasia, ectrodactyly and macular dystrophy) syndrome is a similar condition and is associated with hypotrichosis and macular dystrophy with the additional features of ectodermal dysplasia and ectrodactyly.
Few cases of HJMD have been described in the literature. Sprecher at al. (2001) described several affected Israeli families who were born with normal hair, developed scalp alopecia at an age of 3 months and subsequently had spontaneous regrowth of short, sparse hair during puberty. Pili torti and fusiform beading along the hair shaft was seen on examination by light and scanning electron microscopy. Affected individuals developed progressive macular degeneration and fundus examination revealed pigmentary abnormalities with atrophic changes at the posterior pole extending beyond the macular region. Leibu at al. (2006) performed a fundus examination on 16 affected individuals which also revealed retinal abnormalities extending beyond the macula to more peripheral areas The authors therefore suggested that hypotrichosis with cone-rod dystrophy would be a more appropriate name for the disorder.
The defective gene in HJMD is CDH3, encoding P-cadherin, which is expressed in the retinal pigment epithelium and hair follicles.
Diagnosis is made by assessment of the clinical features of hair loss and reduced visual acuity in childhood. Genomic DNA should be analysed for a CDH3 gene mutation in order to confirm the diagnosis and assist with genetic counselling. No other diagnostic tests are available at present and no genotype-phenotype correlation has been established for the hair or retinal changes and the location of the mutation along the CDH3 gene.
Here is no effective treatment for congenital hypotrichosis and therefore cosmetic camouflage with wigs may be the best management option. Affected individuals with HJMD require regular assessment by an ophthalmologist in order to establish the extent of progression of macular degeneration.