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Title: Deletion 17p11.2 (Smith-Magenis syndrome) is relatively common among patients having mental retardation and myopia

Abstract

We recently reported the finding of moderate to severe myopia in 6 of 10 patients with Smith-Magenis syndrome (SMS). To investigate the prevalence of SMS among mentally retarded people having myopia, we surveyed a cohort of patients residing at a facility for individuals with mental retardation (MR). Of 547 institutionalized individuals with MR, 72 (13.2%) had moderate to high myopia defined as a visual acuity of minus 3 diopters or more. It should be noted that our institution does not specifically select for people with visual impairment; rather, the facility serves people with a primary diagnosis of MR. Sixty-five of 72 (90.3%) myopic individuals identified were available for cytogenetic analysis. Seventeen (26.2%) of these patients had trisomy 21. Down syndrome (DS) is well known to be associated with eye abnormalities, including myopia. Of 48 individuals with moderate to high myopia not having DS, 5 (10.4%) were shown to have deletions of 17p11.2. This is a high prevalence considering the relative rarity of SMS. By contrast, in a randomized sample of 48 patients without significant myopia at the same facility, we found no individuals with deletion 17p11.2. We conclude that the diagnosis of SMS should be considered in any non-Down syndromemore » individual having MR and myopia, and that ophthalmologists serving people with MR should be made aware of this deletion syndrome. Furthermore, our results suggest that significant numbers of people having SMS could be identified through selective institutional screening of patients having a combination of MR and moderate to severe myopia.« less

Authors:
;  [1];  [2]
  1. Elwyn, Inc. PA (United States)
  2. Jefferson Medical College, Philadelphia, PA (United States)
Publication Date:
OSTI Identifier:
133678
Report Number(s):
CONF-941009-
Journal ID: AJHGAG; ISSN 0002-9297; TRN: 95:005313-0408
Resource Type:
Journal Article
Resource Relation:
Journal Name: American Journal of Human Genetics; Journal Volume: 55; Journal Issue: Suppl.3; Conference: 44. annual meeting of the American Society of Human Genetics, Montreal (Canada), 18-22 Oct 1994; Other Information: PBD: Sep 1994
Country of Publication:
United States
Language:
English
Subject:
55 BIOLOGY AND MEDICINE, BASIC STUDIES; HUMAN CHROMOSOME 17; CHROMOSOMAL ABERRATIONS; PATIENTS; MENTAL DISORDERS; SENSE ORGANS DISEASES; DOWNS SYNDROME; SCREENING; HUMAN CHROMOSOME 21; DIAGNOSTIC TECHNIQUES

Citation Formats

Finucane, B., Jaeger, E.R., and Freitag, S.K. Deletion 17p11.2 (Smith-Magenis syndrome) is relatively common among patients having mental retardation and myopia. United States: N. p., 1994. Web.
Finucane, B., Jaeger, E.R., & Freitag, S.K. Deletion 17p11.2 (Smith-Magenis syndrome) is relatively common among patients having mental retardation and myopia. United States.
Finucane, B., Jaeger, E.R., and Freitag, S.K. 1994. "Deletion 17p11.2 (Smith-Magenis syndrome) is relatively common among patients having mental retardation and myopia". United States. doi:.
@article{osti_133678,
title = {Deletion 17p11.2 (Smith-Magenis syndrome) is relatively common among patients having mental retardation and myopia},
author = {Finucane, B. and Jaeger, E.R. and Freitag, S.K.},
abstractNote = {We recently reported the finding of moderate to severe myopia in 6 of 10 patients with Smith-Magenis syndrome (SMS). To investigate the prevalence of SMS among mentally retarded people having myopia, we surveyed a cohort of patients residing at a facility for individuals with mental retardation (MR). Of 547 institutionalized individuals with MR, 72 (13.2%) had moderate to high myopia defined as a visual acuity of minus 3 diopters or more. It should be noted that our institution does not specifically select for people with visual impairment; rather, the facility serves people with a primary diagnosis of MR. Sixty-five of 72 (90.3%) myopic individuals identified were available for cytogenetic analysis. Seventeen (26.2%) of these patients had trisomy 21. Down syndrome (DS) is well known to be associated with eye abnormalities, including myopia. Of 48 individuals with moderate to high myopia not having DS, 5 (10.4%) were shown to have deletions of 17p11.2. This is a high prevalence considering the relative rarity of SMS. By contrast, in a randomized sample of 48 patients without significant myopia at the same facility, we found no individuals with deletion 17p11.2. We conclude that the diagnosis of SMS should be considered in any non-Down syndrome individual having MR and myopia, and that ophthalmologists serving people with MR should be made aware of this deletion syndrome. Furthermore, our results suggest that significant numbers of people having SMS could be identified through selective institutional screening of patients having a combination of MR and moderate to severe myopia.},
doi = {},
journal = {American Journal of Human Genetics},
number = Suppl.3,
volume = 55,
place = {United States},
year = 1994,
month = 9
}
  • J.M. and H.G. are two unrelated patients that presented at an early age with developmental delay and failure to thrive. Clinical features specific to J.M. include unusual facies, global developmental delay, and clinodactyly of the fifth toe. A cytogenetic analysis of H.G. was performed on amniocytes obtained due to a low MSAFP conducted as part of a routine screening. In both J.M. and H.G., a duplication of chromosome 17p11.2 was discovered. The extent of the duplicated region was determined using single copy DNA probes: cen-D17S58-D17S29-D17S258-D17S71-D17S445-tel. All of the markers were found to be duplicated by dosage analysis except for D17S58.more » FISH analysis of H.G., using the Smith-Magenis diagnostic probe obtained from ONCOR, also detected a duplication in 17p11.2. The chromosome containing the duplication could be the result of unequal crossing over due to a misalignment of the two chromosomes during meiosis I. It has been shown that the markers deleted in Smith-Magenis syndrome (SMS) patients are the same as those markers duplicated in J.M. and H.G. Therefore, the chromosomal duplication in 17p11.2 observed in these two patients could be the reciprocal of the chromosomal deletion seen in Smith-Magenis syndrome patients. Interestingly, a similar reciprocal duplication/deletion event is observed for CMT1A and HNPP (hereditary neuropathy with liability to pressure palsies) just distal to the SMS region.« less
  • J.M. and H.G. are two unrelated male patients with developmental delay. Cytogenetic analysis detected a duplication of 17p11.2 in both patients. The extent of the duplicated region was determined using single copy DNA probes: cen-D17S58-D17S29-D17S258-D17S71-D17S445-D17S122-tel. Four of the six markers, D17S29, D17S258, D17S71, and D17S445, were duplicated by dosage analysis. Fluorescent in situ hybridization (FISH) analysis of H.G., using cosmids for locus D17S29, confirmed the duplication in 17p11.2. Because the deletion that causes the Smith-Magenis syndrome involves the same region of 17p11.2 as the duplication in these patients, the mechanism may be similar to that proposed for the reciprocal deletion/more » duplication event observed in Hereditary Neuropathy with Liability to Pressure Palsies (HNPP) and Charcot-Marie-Tooth Type 1A disease (CMT1A). 30 refs., 3 figs., 1 tab.« less
  • Smith-Magenis syndrome (SMS) is a multiple congenital anomaly, mental retardation (MCA/MR) syndrome associated with deletion of chromosome 17 band p11.2. As part of a multi-disciplinary clinical, cytogenetic, and molecular approach to SMS, detailed clinical studies including radiographic neurologic, developmental, ophthalmologic, otolaryngologic, and audiologic evaluations were performed on 27 SMS patients. Significant findings include otolaryngologic abnormalities in 94%, eye abnormalities in 85%, sleep abnormalities (especially reduced REM sleep) in 75%, hearing impairment in 68% (approximately 65% conductive and 35% sensorineural), scoliosis in 65% brain abnormalities (predominantly ventriculomegaly) in 52%, cardiac abnormalities in at least 37%, renal anomalies (especially duplication of themore » collecting system) in 35%, low thyroxine levels in 29%, low immunoglobulin levels in 23%, and forearm abnormalities in 16%. The measured IQ ranged between 20-78, most patients falling in the moderate range of mental retardation at 40-54, although several patients scored in the mild or borderline range. The frequency of these many abnormalities in SMS suggests that patients should be evaluated thoroughly for associated complications both at the time of diagnosis and at least annually thereafter. 42 refs., 2 figs., 3 tabs.« less
  • Smith-Magenis syndrome (SMS) is a clinically recognizable, multiple congenital anomalies/mental retardation syndrome caused by an interstitial deletion involving band p11.2 of chromosome 17. Toward the molecular definition of the interval defining this microdeletion syndrome, 62 unrelated SMS patients in conjunction with 70 available unaffected parents were molecularly analyzed with respect to the presence or absence of 14 loci in the proximal region of the short arm of chromosome 17. A multifaceted approach was used to determine deletion status at the various loci that combined (1) FISH analysis, (2) PCR and Southern analysis of somatic cell hybrids retaining the deleted chromosomemore » 17 from selected patients, and (3) genotype determination of patients for whom a parent(s) was available at four microsatellite marker loci and at four loci with associated RFLPs. The relative order of two novel anonymous markers and a new microsatellite marker was determined in 17p11.2. The results confirmed that the proximal deletion breakpoint in the majority of SMS patients is located between markers D17S58 (EW301) and D17S446 (FG1) within the 17p11.1-17p11.2 region. The common distal breakpoint was mapped between markers cCI17-638, which lies distal to D17S71, and cCI17-498, which lies proximal to the Charcot Marie-Tooth disease type 1A locus. The locus D17S258 was found to be deleted in all 62 patients, and probes from this region can be used for diagnosis of the SMS deletion by FISH. Ten patients demonstrated molecularly distinct deletions; of these, two patients had smaller deletions and will enable the definition of the critical interval for SMS. 49 refs.« less
  • We describe the clinical manifestations and molecular cytogenetic analysis of three patients with a similar distal deletion: del(8)(p23.1). Case 1: A nine-year-old girl who was the product of a normal pregnancy, with family history of recurrent miscarriages. She has an ASD, development delay and dysmorphic features. Case 2: A three-month-old female who died with a hypoplastic left heart and dysmorphic features. Her non-identical twin sister is healthy. No further family history is available. Case 3: A four-year-old boy who was the product of a normal pregnancy with family history of mental retardation. He has bifid uvula, delayed speech and language,more » and no major malformations or dysmorphic features. High resolution G and R banding revealed in all three patients del(8)(p23.1), but the breakpoint for case 1 and 2 was proximal to 8p23.1 and for case 3 distal to 8p23.1. FISH studies with a chromosome 8 paint probe confirmed that no other rearrangement was involved. Chromosome analysis of the parents of case 3 and mother of case 1 were normal; the remaining parents were not available for study. Eight individual patients and three members in one family with del(8)(p23.1) have been reported in the past five years. Major congenital anomalies, especially congenital heart defect, is most often associated with a breakpoint proximal to 8p23.1 Three patients were detected within a three year period in this study and five cases were found within a four year period by another group, suggesting that the distal 8p deletion may be a relatively common syndrome. This small deletion is easily overlooked (i.e. case 1 and 3 were reported as normal at amniocentesis) and can be associated with few or no major congenital anomalies.« less