Volume 86 Number 3
Letters to the Editor
"Editorial Correspondence" or letters to the Editor relative to articles published in the JOURNAL or to topics of current interest are subject to critical review and to current editorial policy in respect to publication in part or in full.
Twlnning and cleft lip with or without cleft palate To the Editor: During an analysis of 215 families ascertained through an affected sib with cleft lip with or without cleft palate (CL [P]), it was surprising to find a relatively hig h n u m b e r of affected individuals born of twin pregnancies. These women had a total of 1,058 pregnancies (excluding miscarriages); nine of the women bore twins (0.85%). Of these, five included an individual with CL(P), which represents 2.3% of all propositii. The frequency of twinning in this sample was similar to that previously described in the general population of Mexico, of 1.2%. 1 However, the figure for twinning found in the affected individuals (2.3%) is almost 5-fold more than that present in their nontwin sibs (0.47%). We wonder if others have observed similar findings. Since the heritability estimates of CL(P) in our sample, to be published elsewhere, were similar to those described by others,2, 3 the possibility that twinning might be a contributing environmental factor in the development of this anomaly is suggested. S. Armendares Departamento de Investigacidn Cient~ca Secci~n de Gendtica Apartado postal 731032 MExico 73, D.F. MExico R. Lisker Departamento de GenEtica lnstituto Nacional de ta Nutrici~fn MCxieo 22, D.F. M~xico Partially supported by a grant from The Ford Foundation.
REFERENCES 1. Stevenson AC, Johnston HA, Steward MIP, and Golding DR: Congenital malformations. A report of a study of
series of consecutive births in 24 centers, Bull WHO 34(Suppl): 1966. 2. Carter CO: Genetics of common disorders, Br Med Bull 25:52, 1969. ' 3. Woolf CM: Congenital cleft lip. A genetic study of 496 propositi, J Med Genet 8:65, 1971.
Keratosis follicularis as a confusing term To the Editor: Cantu and associates 1 have described a fascinating new syndrome with dwarfism, cerebral atrophy, and a skin eruption in the April, !974, issue of THE JOURNAL. However, I was somewhat perplexed by the use of the term keratosis follicularis for the cutaneous findings in this syndrome, and nowhere in the paper is there a concise description of the clinical morphology of the lesions or the histologic features. Keratosis follicularis is the accepted synonym for Darier's disease; this nomenclature is well established and used in virtually every current textbook of dermatology. 2' 3 Darier's disease is transmitted as an autosomal dominant trait and has a very distinctive histologic pattern. Intraepidermal lacunae form above the basal layer and contain cells which show premature partial keratinization (dyskeratosis). Electron microscopic studies have demonstrated alterations in the tonofilament-desmosome complex. Clinically the lesions consist of coalescent masses of warty, yellow-brown, crusted papules with predilection for the upper chest, back, lumbar, and flexural areas. Although scalp involvement is common, significant alopecia is distinctly unusual. The "rough skin" and alopecia found in affected males of the kindred reported by Cantu and associates may be manifestations of a disorder in which spiny follicular papules, representing keratotic plugs in the hair follicles, result in generalized loss of hair including scalp hair, brows, and lashes (keratosis follicularis spinulosa decalvans), 4' 5 This disease is thought to be transmitted in an X-linked fashion with partial expression of the gene in a proportion of the carrier females. Another syn-