Retinitis pigmentosa, growth hormone deficiency and acromelic skeletal dysplasia in two male siblings: possible familial RHYNS syndrome

Abstract

The combination of retinitis pigmentosa (RP), hypopituitarism, and acromelic, skeletal dysplasia has been rarely observed. Here we report two brothers with RP, growth hormone deficiency and skeletal dysplasia. The proband was diagnosed with RP at age 9 years after short history of blurred vision; his electroretinogram (ERG) was markedly abnormal. Endocrinologic evaluation because of short stature 5 years later was consistent with growth hormone deficiency; gonadotropin deficiency was also confirmed. At 14 years his examination showed the height below the 5th percentile, mild facial asymmetry without ptosis, and acromelic shortening of distal extremities. The proband's brother was diagnosed with growth hormone deficiency at age 3 years and retinitis pigmentosa at 7 years; ERG was abnormal. He had a history of severe ptosis and mild hearing loss. Examination at age 10 years showed bilateral ptosis, facial asymmetry with right sided maxillary hypoplasia, prognathia and acromelic shortening. Both brothers had normal renal ultrasound. A routine chromosomal analysis was normal. The family history was non-contributory without known consanguinity; both parents were reportedly normal.The concurrence of RP, hypopituitarism and skeletal dysplasia is very rare. Two unrelated boys with similar features plus renal impairment were reported previously, and a potential syndrome RHYNS was suggested (Retinitis pigmentosa, Hypopituitarism, Nephronophtisis and Skeletal dysplasia). We propose that the clinical picture of these brothers is consistent with RHYNS and that they represent the first instance of a familial occurrence of this syndrome. RP, hypopituitarism and acromelic skeletal dysplasia are cardinal features of RHYNS syndrome and were present in all four reported cases. Nepronophtisis may be absent, at least at the beginning of the disease. The presence of RHYNS in two siblings supports an autosomal recessive mode of inheritance. However, since all 4 known cases are males, this condition may be inherited as an X-linked disorder. Even though we did not detect a microdeletion, this clinical variability may be due to contiguous genes syndrome.