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Bardet-Biedl syndrome 2(BBS2)

MedGen UID:
422453
Concept ID:
C2936863
Disease or Syndrome
Synonym: BBS2
 
Gene (location): BBS2 (16q13)
 
Monarch Initiative: MONDO:0014432
OMIM®: 615981

Definition

BBS2 is an autosomal recessive ciliopathy characterized by retinal degeneration, polydactyly, renal disease, hypogonadism, obesity, dysmorphic features, and variable degrees of cognitive impairment (Innes et al., 2010). Mutation in the BBS2 gene is the third most frequent cause of BBS, accounting for approximately 8% of cases (Zaghloul and Katsanis, 2009). For a general phenotypic description and a discussion of genetic heterogeneity of Bardet-Biedl syndrome, see BBS1 (209900). [from OMIM]

Clinical features

From HPO
External genital hypoplasia
MedGen UID:
344478
Concept ID:
C1855333
Finding
Underdevelopment of part or all of the external reproductive organs.
Postaxial hand polydactyly
MedGen UID:
609221
Concept ID:
C0431904
Congenital Abnormality
Supernumerary digits located at the ulnar side of the hand (that is, on the side with the fifth finger).
Postaxial foot polydactyly
MedGen UID:
384489
Concept ID:
C2112129
Finding
Polydactyly of the foot most commonly refers to the presence of six toes on one foot. Postaxial polydactyly affects the lateral ray and the duplication may range from a well-formed articulated digit to a rudimentary digit.
Primary dilated cardiomyopathy
MedGen UID:
2880
Concept ID:
C0007193
Disease or Syndrome
Familial dilated cardiomyopathy is a genetic form of heart disease. It occurs when heart (cardiac) muscle becomes thin and weakened in at least one chamber of the heart, causing the open area of the chamber to become enlarged (dilated). As a result, the heart is unable to pump blood as efficiently as usual. To compensate, the heart attempts to increase the amount of blood being pumped through the heart, leading to further thinning and weakening of the cardiac muscle. Over time, this condition results in heart failure.\n\nIt usually takes many years for symptoms of familial dilated cardiomyopathy to cause health problems. They typically begin in mid-adulthood, but can occur at any time from infancy to late adulthood. Signs and symptoms of familial dilated cardiomyopathy can include an irregular heartbeat (arrhythmia), shortness of breath (dyspnea), extreme tiredness (fatigue), fainting episodes (syncope), and swelling of the legs and feet. In some cases, the first sign of the disorder is sudden cardiac death. The severity of the condition varies among affected individuals, even in members of the same family.
Atrial septal defect
MedGen UID:
6753
Concept ID:
C0018817
Congenital Abnormality
Atrial septal defect (ASD) is a congenital abnormality of the interatrial septum that enables blood flow between the left and right atria via the interatrial septum.
Bicuspid aortic valve
MedGen UID:
57436
Concept ID:
C0149630
Congenital Abnormality
Aortic valve disease-2 (AOVD2) is characterized by bicuspid aortic valve (BAV) and dilation of the ascending aorta. Calcification of the valve and the aorta has been observed, and some patients exhibit coarctation of the aorta (Tan et al., 2012; Luyckx et al., 2019; Park et al., 2019). For a general phenotypic description and a discussion of genetic heterogeneity of aortic valve disease, see AOVD1 (109730).
Obesity
MedGen UID:
18127
Concept ID:
C0028754
Disease or Syndrome
Accumulation of substantial excess body fat.
Global developmental delay
MedGen UID:
107838
Concept ID:
C0557874
Finding
A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.
Intellectual disability
MedGen UID:
811461
Concept ID:
C3714756
Mental or Behavioral Dysfunction
Intellectual disability, previously referred to as mental retardation, is characterized by subnormal intellectual functioning that occurs during the developmental period. It is defined by an IQ score below 70.
Diabetes mellitus
MedGen UID:
8350
Concept ID:
C0011849
Disease or Syndrome
A group of abnormalities characterized by hyperglycemia and glucose intolerance.
Hypogonadism
MedGen UID:
5711
Concept ID:
C0020619
Disease or Syndrome
A decreased functionality of the gonad.
Retinal degeneration
MedGen UID:
48432
Concept ID:
C0035304
Finding
A nonspecific term denoting degeneration of the retinal pigment epithelium and/or retinal photoreceptor cells.
Rod-cone dystrophy
MedGen UID:
1632921
Concept ID:
C4551714
Disease or Syndrome
An inherited retinal disease subtype in which the rod photoreceptors appear to be more severely affected than the cone photoreceptors. Typical presentation is with nyctalopia (due to rod dysfunction) followed by loss of mid-peripheral field of vision, which gradually extends and leaves many patients with a small central island of vision due to the preservation of macular cones.

Professional guidelines

PubMed

Rao PV, Lu X, Pattee P, Turner M, Nandgaonkar S, Paturi BT, Roberts CT Jr, Nagalla SR
J Assoc Physicians India 2005 Jun;53:521-6. PMID: 16121806

Curated

Slavotinek A, Beales P
Eur J Hum Genet 2011 Mar;19(3) Epub 2010 Dec 8 doi: 10.1038/ejhg.2010.199. PMID: 21150877Free PMC Article

Recent clinical studies

Etiology

Rao PV, Lu X, Pattee P, Turner M, Nandgaonkar S, Paturi BT, Roberts CT Jr, Nagalla SR
J Assoc Physicians India 2005 Jun;53:521-6. PMID: 16121806

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