To the Editor: Lynch and de la Chapelle (March 6 issue)1 emphasizethe screening of high-risk patients who have a mutation in theadenomatous polyposis coli (APC) gene or who have one or morefirst-degree relatives with familial adenomatous polyposis.However, the importance of ophthalmic examination in screeningfor and diagnosis of familial adenomatous polyposis is not noted.Congenital hypertrophy of retinal pigment epithelium is themost prominent extracolonic manifestation of familial adenomatouspolyposis and is present in about 90 percent of patients.2,3,4This condition can be identified by noninvasive methods evenin infants and young children by simple fundus examination withthe pupils dilated. A combined approach involving the detectionof an APC mutation and detection of congenital hypertrophy ofretinal pigment epithelium for presymptomatic diagnosis of familialadenomatous polyposis is highly recommended.5
Wai Man Chan, M.R.C.P., F.R.C.S. Chi Pui Pang, D.Phil. Dennis S.C. Lam, F.R.C.S., F.R.C.Ophth. Chinese University of Hong Kong Kowloon, Hong Kong dennislam{at}cuhk.edu.hk
References
Lynch HT, de la Chapelle A. Hereditary colorectal cancer. N Engl J Med 2003;348:919-932. [Free Full Text]
Pang CP, Fan DS, Keung JW, et al. Congenital hypertrophy of the retinal pigment epithelium and APC mutations in Chinese with familial adenomatous polyposis. Ophthalmologica 2001;215:408-411. [Medline]
Valanzano R, Cama A, Volpe R, et al. Congenital hypertrophy of the retinal pigment epithelium in familial adenomatous polyposis: novel criteria of assessment and correlations with constitutional adenomatous polyposis coli gene mutations. Cancer 1996;78:2400-2410. [CrossRef][Medline]
Lam DSC, Kwok SPY, Kwok AKH, Liew CT, Lau JWY, Pang CC. Incidence and predictive value of congenital hypertrophy of retinal pigment epithelium in Chinese familial adenomatous polyposis patients. Chin Med J (Engl) 1998;111:278-281. [Medline]
Pang CP, Lam DS. Differential occurrence of mutations causative of eye diseases in the Chinese population. Hum Mutat 2002;19:189-208. [CrossRef][Web of Science][Medline]
To the Editor: In Table 3 of the review article by Lynch andde la Chapelle, microcephaly is listed as one of the phenotypicfeatures of the Bannayan–Ruvalcaba–Riley syndrome.In fact, patients with this syndrome have macrocephaly1 (withnormal-size ventricles). Typically, their birth weight is greaterthan 4 kg and their birth length above the 97th percentile,but their final height as adults is within the normal range.2In addition, 50 percent of the patients have hypotonia, delayedgross motor or speech development, or mental retardation.2 Inabout 60 percent of the patients, a myopathic process affectingthe proximal muscles is present.2
Karen W. Gripp, M.D. A.I. duPont Hospital for Children Wilmington, DE 19803 kgripp{at}nemours.org
References
Gorlin RJ, Cohen MM Jr, Condon LM, Burke BA. Bannayan-Riley-Ruvalcaba syndrome. Am J Med Genet 1992;44:307-314. [CrossRef][Web of Science][Medline]
Jones KL. Smith's recognizable patterns of human malformation. 5th ed. Philadelphia: W.B. Saunders, 1997.
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