Indian Journal of Dermatology
CORRESPONDENCE
Year
: 2011  |  Volume : 56  |  Issue : 3  |  Page : 347--349

Cytogenetics: A new tool for early diagnosis and prognosis of tuberous sclerosis?


Ashish Singh1, S Ambujam1, AN Uma2,  
1 Department of Dermatlogy, Venereology and Leprology, Mahatma Gandhi Medical College & Research Institute, Pillaiyarkuppam, Pondicherry, India
2 Department of Anatomy, Mahatma Gandhi Medical College & Research Institute, Pillaiyarkuppam, Pondicherry, India

Correspondence Address:
S Ambujam
Department of Dermatlogy, Venereology and Leprology, Mahatma Gandhi Medical College & Research Institute, Pillaiyarkuppam, Pondicherry
India




How to cite this article:
Singh A, Ambujam S, Uma A N. Cytogenetics: A new tool for early diagnosis and prognosis of tuberous sclerosis?.Indian J Dermatol 2011;56:347-349


How to cite this URL:
Singh A, Ambujam S, Uma A N. Cytogenetics: A new tool for early diagnosis and prognosis of tuberous sclerosis?. Indian J Dermatol [serial online] 2011 [cited 2020 Jul 3 ];56:347-349
Available from: http://www.e-ijd.org/text.asp?2011/56/3/347/82507


Full Text

Sir,

Chromosomes are rod-shaped structures with two chromatids held together at centromere. In acrocentric subtype of chromosomes i.e. chromosome nos. 13, 14, 15, 21, 22, centromere lies near one end. [1],[2] Sticky substance formed during meiosis keeps tips of short arms closer and grouping of chromosomes occurs. [3] It is known as acrocentric association (A.A.). [2] Previously acrocentric association has been detected in Down's syndrome, Turner's syndrome, Klinefelter's syndrome and in recurrent aborters. [4] In fact, the authors have noticed significant A.A. in a 10- year-old girl with Monilethrix. A.A. accounts for elevated incidence of chromosomal rearrangements and consequently can cause chromosomal diseases. [2]

A 33-year-old woman presented to us with multiple erythematous/ hyperpigmented angiofibroma over nasolabial fold, nose, cheeks. In addition, the patient had multiple Shagreen patches over the back [Figure 1]. Nail examination showed periungual fibroma with onycholysis involving many of the toe nails and a few finger nails [Figure 2]. Dental examination showed presence of pitting.{Figure 1}{Figure 2}

A 25-year-old man, sibling of the above patient, presented with similar number of facial lesions (angiofibroma), limited involvement of nails and single Shagreen patch [Figure 3] and [Figure 4]. Based on the clinical features, we diagnosed tuberous sclerosis in both patients.{Figure 3}{Figure 4}

Cytogenetic study was done for both the patients, and results showed 60% of A.A. in the first patient; 36%, in the second patient; while A.A. was 27% for the control of the first patient and 18% for the control of the second patient [Figure 5] and [Figure 6].{Figure 5}{Figure 6}

In the present case, high degree of A.A. in patients compared to controls may indicate the diagnostic utility of cytogenetic study in Tuberous Sclerosis; and higher degree of A.A. in the first patient compared to second and more clinical features in the first patient compared to second may indicate utility of cytogenetic study in predicting the extent and severity, when the disease is diagnosed early. Higher degree of acrocentric association in both the patients in comparison to controls may indicate some association between acrocentric association and mutation of TSC1 and TSC2 genes. [5]

Cytogenetic studies have not been extensively applied in genodermatoses. However, the authors feel that detection of Acrocentric Association in genodermatoses like Bloom syndrome, tuberous sclerosis, Monilethrix, may have a predictive value. Hence early detection and counseling both the parents and patients may help them to live and cope with the disease.

References

1Henderson AS, Warburton D, Dvalishvili N, Jokhadze T. Letter: Ribosomal DNA connectives between human acrocentric chromosomes. Nature 1973 Sep 14;245:95-7.
2Lezhava T, Tsigroshvili Z, Dvalishvili N, Jokhadze T. Mathematical model for satellite associations of human acrocentric chromosomes. Georgian Med News 2008;(164):90-9.
3Zellweger H, Abbo G,Cuany R. Satellite association and translocation mongolism. J Med Genet 1966;3:186-9.
4Vishwanath A, David S, Rajangam S, Thomas M. Down Syndrome: Acrocentric association. Ind J Hum Genet 1996; 2:131-4
5Cheadle JP, Reeve MP, Sampson JR, Kwiatkowski DJ. Molecular genetic advances in tuberous sclerosis. Hum Genet 2000;107:97-114.