A RARE CAUSE OF OBESITY: BARDET BIEDLE SYNDROME

Öz

Bardet Biedle Syndrome is a pleiotropic disorder with variable expressivity. Up to date fourteen BBS gene mutations have been reported. Primary cilia are microtubule-based membrane projections located at the surface of many cells and defects in primary cilia formation have been implicated in Bardet-Biedl Syndrome. The disorder is characterised by retinitis pigmentosa, truncal obesity, polydactly, hypogonadism, renal dysfunction, developmental delay, speech delay, learning difficulties and diabetes mellitus. We present a case with obesity (height: 175, weight: 112, body mass index: 36,9kg/m2), diabetes mellitus, retinitis pigmentosa, polydactly and mild mental retardation. By studying his family medical records we identified one relative (his brother not alive) with suggestive clinical findings for Bardet Biedl syndrome. The patient was on intensive insulin therapy for diabetes. His cardiac examination and echocardiography was normal. His renal functions (blood urea, creatinine) were also normal. By presenting our case we wanted to point out a rare cause of obesity. Early diagnosis and symptomatic, supportive and rehabilitative measures can reduce the disability. 

Anahtar Kelimeler

• Bardet Biedle Syndrome
• pleiotropic
• disorder

OBEZİTENİN NADİR BİR NEDENİ: BARDET BİEDLE SENDROMU

Öz

Bardet-Biedl Sendromu (BBS), pleitropik bir bozukluk olup değişken genetik geçişi mevcuttur. Bugüne kadar 14 adet BBS gen mutasyonu bildirilmiştir. Siller birçok hücrenin yüzeyinde bulunan mikrotübül çıkıntılardır ve Bardet Biedle Sendromunda bu sil yapılarında bozukluk tespit edilmiştir. Bu sendromda retinitis pigmentoza, gövdesel obezite, polidaktili, hipogonadizm, renal fonksiyon bozukluğu, gelişme geriliği ve konuşmada gecikme, öğrenme bozuklukları ve diyabetes mellitus yer alır. Obezitesi (Boy:175cm, kilo: 112kg, vücut kitle indeksi: 36,9kg/m2), diyabetes mellitus, retinitis pigmentoza, polidaktili ve hafif mental retardasyonu olan bir vakayı sunduk. Aile öyküsünden bir akrabasında (erkek kardeşinde halen hayatta değil) Bardet Biedle Sendromunu düşündüren bulgular mevcuttu. Hastamız çoklu insülin tedavisi altındaydı. Kardiyak muayenesi ve ekokardiyografisi normaldi. Renal fonksiyon testleri de (üre, kreatinin) normaldi. Bu vakayla birlikte obezitenin nadir bir nedenini gözden geçirmeyi planladık. Erken tanı, semptoma yönelik destek ve rehabilitasyonlar komplikasyonları azaltabilir.

ABSTRACT

Bardet Biedle Syndrome is a pleiotropic disorder with variable expressivity. Up to date fourteen BBS gene mutations have been reported. Primary cilia are microtubule-based membrane projections located at the surface of many cells and defects in primary cilia formation have been implicated in Bardet-Biedl Syndrome. The disorder is characterised by retinitis pigmentosa, truncal obesity, polydactly, hypogonadism, renal dysfunction, developmental delay, speech delay, learning difficulties and diabetes mellitus. We present a case with obesity (height: 175, weight: 112, body mass index: 36,9kg/m2), diabetes mellitus, retinitis pigmentosa, polydactly and mild mental retardation. By studying his family medical records we identified one relative (his brother not alive) with suggestive clinical findings for Bardet Biedl syndrome. The patient was on intensive insulin therapy for diabetes. His cardiac examination and echocardiography was normal. His renal functions (blood urea, creatinine) were also normal. By presenting our case we wanted to point out a rare cause of obesity. Early diagnosis and symptomatic, supportive and rehabilitative measures can reduce the disability.

Anahtar Kelimeler

• Obezite
• Bardet Biedle Sendromu
• pleitropik bir bozukluk

Kaynakça

1. 1. Muller J, Stoetzel C, Vincent MC, Leitch CC, Laurier V, Danse JM, et al. Identification of 28 novel mutations in the Bardet-Biedl syndrome genes: the burden of private mutations in an extensively heterogeneous disease. Hum Genet. 2010 Mar;127(5): 583-93.
2. 2. Blacque OE, Reardon MJ, Li C, McCarthy J, Mahjoub MR, Ansley SJ, et al. Loss of C. elegans BBS-7 and BBS-8 protein function results in cilia defects and compromised intraflagellar transport. Genes Dev. 2004 Jul 1;18(13): 1630-42.
3. 3. Badano JL, Mitsuma N, Beales PL, Katsanis N. The ciliopathies: an emerging class of human genetic disorders. Annu Rev Genomics Hum Genet. 2006; 7: 125-48.
4. 4. Webb MP, Dicks EL, Green JS, Moore SJ, Warden GM, Gamberg JS, et al. Autosomal recessive Bardet-Biedl syndrome: first-degree relatives have no predisposition to metabolic and renal disorders. Kidney Int. 2009 Jul; 76(2): 215-23.
5. 5. Iannello S, Bosco P, Cavaleri A, Camuto M, Milazzo P, Belfiore F. A review of the literature of Bardet-Biedl disease and report of three cases associated with metabolic syndrome and diagnosed after the age of fifty. Obes Rev. 2002 May; 3(2): 123-35.