How common are the congenital ichthyoses? How are they inherited?

Ichthyosis vulgaris: Incidence of 1:250; autosomal dominant
X-linked ichthyosis: Incidence of 1:6000; X-linked recessive
Epidermolytic hyperkeratosis: Incidence of 1:300,000; autosomal dominant
Congenital ichthyosiform erythroderma (CIE): Incidence of 1:100,000; autosomal recessive
Lamellar ichthyosis: Incidence of 1:300,000; autosomal recessive
Harlequin fetus: Rare; autosomal recessive
Akiyama M: The clinical spectrum of nonbullous congenital ichthyosiform erythroderma and lamellar ichthyosis, Clin Exp Dermatol 28(3):235–240, 2003.
DiGiovanna J: Ichthyosis: etiology, diagnosis, and management, Am J Clin Dermatol 4(2):81–95, 2003.
Shwayder T: Disorders of keratinization: diagnosis and management, Am J Clin Dermatol 5(1):17–29, 2004.