Introduction
Background
Rud syndrome, previously considered a rare recessive disorder marked by ichthyosis, hypogonadism, mental retardation, epilepsy, and dwarfism, is now classified as an ichthyosis. The contemporary ichthyosis classification reassigns it as a neuroichthyosis with cutaneous findings most similar to those observed in X-linked recessive ichthyosis, rather than a distinct clinical entity. Although ichthyosis and hypogonadism are the predominant features, neurologic deficits vary, suggesting genetic heterogeneity.
Pathophysiology
The pathophysiology of Rud syndrome is unknown. Defects in steroid sulfatase and Kallmann loci on the X chromosome have been identified; however, these defects were not tested in most of the earlier cases. Cases suggestive of an autosomal recessive inheritance pattern have also been reported.
Frequency
International
The prevalence is rare worldwide.
Mortality/Morbidity
Mortality and morbidity depend on the presence and the severity of associated findings.
Race
No racial predilection is known.
Sex
Cases in which steroid sulfatase deficiency has been identified involved boys; however, overall, no male predilection is apparent, as anticipated by an X-linked recessive genodermatosis. This observation could be explained by the fact that a defect in an autosomal recessive gene may also be present (some cases suggestive of this inheritance pattern have been reported) or that such heterogeneity of clinical and genetic findings exists and some patients who are thought to have Rud syndrome really have different disorders manifesting with clinical changes similar to those of Rud syndrome.
Age
The disease manifests with clinical signs and symptoms at birth or shortly thereafter.
Clinical
History
- The most prominent feature of Rud syndrome is ichthyosis, which is congenital or present soon after birth.
- Neurologic findings are generally inconstant; however, mental retardation and epilepsy have been described in the literature as cardinal features.
Physical
- Ichthyosis has a predilection for the extensor extremities and can vary from a mild generalized branny desquamation to a severe flaky scaling that resembles snakeskin. Other cutaneous manifestations reported include acanthosis nigricans and alopecia.
- Skeletal defects include short stature, arachnodactyly, hypoplastic or absent teeth, and structural abnormalities of the hands and the feet.
- Neurologically, frequent seizures pose difficulty in long-term treatment. Other neurologic features include anosmia and hypertrophic polyneuropathy. Ophthalmologic defects include retinitis pigmentosa, strabismus, ptosis, blepharospasm, nystagmus, and cataracts.
- Hypogonadism, which may be primary or hypogonadotrophic in origin, is more easily recognized in males who tend to be eunuchoid in appearance. Eunuchoid features include thin, soft, pale skin, which is not oily because the sebaceous glands and apocrine glands are dormant; absent secondary sexual characteristics, such as a small penis, poorly furrowed scrotal skin, and lack of beard, axillary, and pubic hair; straight hairline over the forehead and low hairline over the temples; poor muscle development; excessive subcutaneous fat in the pectoral and girdle regions; and long arms and legs secondary to delayed closure of the epiphyses, with resultant prolonged growth of the long bones.
Causes
- Genetic mutations are the cause; both autosomal recessive inheritance and X-linked recessive inheritance have been reported.
- A genetic defect may be a cause. Although unknown, the genetic defect is suspected to involve a deletion of the steroid sulfatase locus.
- The heterogeneity of the genetic abnormalities may account for the presence of X-linked ichthyosis–like skin changes in male and female patients.
More on Rud Syndrome |
 Overview: Rud Syndrome |
| Differential Diagnoses & Workup: Rud Syndrome |
| Treatment & Medication: Rud Syndrome |
| Follow-up: Rud Syndrome |
| References |
| Next Page » |
References
Andria G, Ballabio A, Parenti G, Di Maio S, Piccirillo A. Steroid sulphatase deficiency is present in patients with the syndrome 'ichthyosis and male hypogonadism' and with 'Rud syndrome'. J Inherit Metab Dis. 1984;7 Suppl 2:159-60. [Medline].
Kaufman LM. A syndrome of retinitis pigmentosa, congenital ichthyosis, hypergonadotropic hypogonadism, small stature, mental retardation, cranial dysmorphism, and abnormal electroencephalogram. Ophthalmic Genet. Jun 1998;19(2):69-79. [Medline].
Larbrisseau A, Carpenter S. Rud syndrome: congenital ichthyosis, hypogonadism, mental retardation, retinitis pigmentosa and hypertrophic polyneuropathy. Neuropediatrics. May 1982;13(2):95-8. [Medline].
Maldonado RR, Tamayo L, Carnevale A. Neuroichthyosis with hypogonadism (Rud's syndrome). Int J Dermatol. Jun 1975;14(5):347-52. [Medline].
Marxmiller J, Trenkle I, Ashwal S. Rud syndrome revisited: ichthyosis, mental retardation, epilepsy and hypogonadism. Dev Med Child Neurol. Jun 1985;27(3):335-43. [Medline].
Münke M, Kruse K, Goos M, Ropers HH, Tolksdorf M. Genetic heterogeneity of the ichthyosis, hypogonadism, mental retardation, and epilepsy syndrome. Clinical and biochemical investigations on two patients with Rud syndrome and review of the literature. Eur J Pediatr. Oct 1983;141(1):8-13. [Medline].
Stoll C, Eyer D. A syndrome of congenital ichthyosis, hypogonadism, small stature, facial dysmorphism, scoliosis and myogenic dystrophy. Ann Genet. 1999;42(1):45-50. [Medline].
Sybert VP. Ichthyosis with hypogonadism. In: Genetic Skin Disorders. ed. New York, NY: Oxford University Press; 1997:114-5.
Tercedor J, García A. [Keratotic neurocutaneous syndromes]. Rev Neurol. Sep 1997;25 Suppl 3:S238-42. [Medline].
Kuniba H, Egashira M, Motomura H, Motomura K, Kondoh T. [Rud syndrome]. Nippon Rinsho. Sep 28 2006;Suppl 3:485-7. [Medline].
Further Reading
Keywords
ichthyosis with hypogonadism, neuroichthyosis, ichthyosis, hypogonadism, mental retardation, epilepsy, dwarfism
