| | Bacterial gastroenteritis |
| | Bagatelle Cassidy syndrome |
| | Balo's concentric sclerosis |
| | Baraitser Brett Piesowicz syndrome |
| | Baraitser Rodeck Garner syndrome |
| | Bardet-Biedl syndrome, type 1 |
| | Bardet-Biedl syndrome, type 2 |
| | Bardet-Biedl syndrome, type 3 |
| | Bardet-Biedl syndrome, type 4 |
| | Bare lymphocyte syndrome 2 |
| | Barnicoat Baraitser syndrome |
| | Barrow Fitzsimmons syndrome |
| | Bartter syndrome, antenatal form |
| | Bartter syndrome, classic form |
| | Basal cell nevus anodontia abnormal bone mineralization |
| | Basilar impression primary |
| | Batten Turner muscular dystrophy |
| | Bazex-Dupre-Christol syndrome |
| | Bazopoulou Kyrkanidou syndrome |
| | Becker's muscular dystrophy |
| | Beemer Ertbruggen syndrome |
| | Behrens Baumann Dust syndrome |
| | Bellini Chiumello Rinoldi syndrome |
| | Ben Ari Shuper Mimouni syndrome |
| | Benallegue Lacete syndrome |
| | Benign autosomal dominant myopathy |
| | Benign congenital hypotonia |
| | Benign essential blepharospasm |
| | Benign essential tremor syndrome |
| | Benign familial hematuria |
| | Benign familial infantile convulsions |
| | Benign familial infantile epilepsy |
| | Benign fasciculation syndrome |
| | Benign mucosal pemphigoid |
| | Benign paroxysmal positional vertigo |
| | Bentham Driessen Hanveld syndrome |
| | Berardinelli-Seip congenital lipodystrophy |
| | Berry aneurysm, cirrhosis, pulmonary emphysema, and cerebral calcification |
| | Besnier-Boeck-Schaumann disease |
| | Beta ketothiolase deficiency |
| | Beta-galactosidase-1 deficiency |
| | Beta-thalassemia major anemia |
| | Beta-thalassemia (gene promoter involvement) |
| | Bhaskar Jagannathan syndrome |
| | Bickel Fanconi glycogenosis |
| | Bidirectional tachycardia |
| | Bilateral renal agenesis dominant type |
| | Biliary atresia, extrahepatic |
| | Biliary atresia, intrahepatic, non syndromic form |
| | Biliary atresia, intrahepatic, syndromic form |
| | Biliary malformation renal tubular insufficiency |
| | Billard Toutain Maheut syndrome |
| | Bindewald Ulmer Muller syndrome |
| | Bird headed dwarfism Montreal type |
| | Birdshot chorioretinopathy |
| | Bixler Christian Gorlin syndrome |
| | Blepharo cheilo dontic syndrome |
| | Blepharo facio skeletal syndrome |
| | Blepharo naso facial syndrome Van maldergem type |
| | Blepharonasofacial malformation syndrome |
| | Blepharophimosis nasal groove growth retardation |
| | Blepharophimosis ptosis esotropia syndactyly short |
| | Blepharophimosis ptosis syndactyly mental retardation |
| | Blepharophimosis syndrome Ohdo type |
| | Blepharophimosis, ptosis, epicanthus inversus |
| | Blepharoptosis aortic anomaly |
| | Blepharoptosis cleft palate ectrodactyly dental anomalies |
| | Blepharoptosis myopia ectopia lentis |
| | Blethen Wenick Hawkins syndrome |
| | Blood Coagulation Disorders, Inherited |
| | Bone development disorder |
| | Bone dysplasia Azouz type |
| | Bone dysplasia corpus callosum agenesis |
| | Bone dysplasia lethal Holmgren type |
| | Bone dysplasia Moore type |
| | Bone fragility craniosynostosis proptosis hydrocephalus |
| | Bone marrow failure neurologic abnormalities |
| | Bone tumor (generic term) |
| | Bonneau-Beaumont syndrome |
| | Bonneman Meinecke Reich syndrome |
| | Bonnemann Meinecke syndrome |
| | Bonnevie Ullrich Turner syndrome |
| | Booth Haworth Dilling syndrome |
| | Bork Stender Schmidt syndrome |
| | Borrone Di Rocco Crovato syndrome |
| | Boscherini Galasso Manca Bitti syndrome |
| | Bosma Henkin Christiansen syndrome |
| | Boucher Neuhauser syndrome |
| | Boudhina Yedes Khiari syndrome |
| | Bourneville's disease or Bourneville-Pringle disease |
| | Bowing congenital short bones |
| | Bowing of long bones congenital |
| | Boylan Dew Greco syndrome |
| | Brachioskeletogenital syndrome |
| | Brachman-de Lange syndrome |
| | Brachycephalofrontonasal dysplasia |
| | Brachycephaly deafness cataract mental retardation |
| | Brachydactylous dwarfism Mseleni type |
| | Brachydactyly absence of distal phalanges |
| | Brachydactyly clinodactyly |
| | Brachydactyly dwarfism mental retardation |
| | Brachydactyly elbow wrist dysplasia |
| | Brachydactyly hypertension |
| | Brachydactyly long thumb type |
| | Brachydactyly mesomelia mental retardation heart defects |
| | Brachydactyly nystagmus cerebellar ataxia |
| | Brachydactyly preaxial hallux varus |
| | Brachydactyly scoliosis carpal fusion |
| | Brachydactyly small stature face anomalies |
| | Brachydactyly Smorgasbord type |
| | Brachydactyly tibial hypoplasia |
| | Brachydactyly type A5 nail dysplasia |
| | Brachydactyly types B and E combined |
| | Brachymesomelia renal syndrome |
| | Brachymesophalangy 2 and 5 |
| | Brachymesophalangy mesomelic short limbs osseous anomalies |
| | Brachymesophalangy type 2 |
| | Brachymetapody anodontia hypotrichosis albinoidism |
| | Brachymorphism onychodysplasia dysphalangism syndrome |
| | Brachyolmia recessive Hobaek type |
| | Brachytelephalangy characteristic facies Kallmann |
| | Braddock Jones Superneau syndrome |
| | Branchial arch syndrome X linked |
| | Branchio oculo facial syndrome Hing type |
| | Branchio-oculo-facial syndrome |
| | Branchiootorenal syndrome |
| | Breast and ovarian cancer |
| | Brittle bone syndrome lethal type |
| | Broad-betalipoproteinemia |
| | Bronchiectasis oligospermia |
| | Bronchiolitis obliterans with obstructive pulmonary disease |
| | Bronchiolotis obliterans organizing pneumonia (BOOP) |
| | Bronchopulmonary amyloidosis |
| | Bronchopulmonary dysplasia |
| | Bruton type agammaglobulinemia |
| | Bulbospinal amyotrophy, X-linked |
| | Bullous dystrophy macular type |
| | Bullous ichtyosiform erythroderma congenita |
| | Buntinx Lormans Martin syndrome |
| | Burnett Schwartz Berberian syndrome |
| | Burning mouth syndrome- Type 3 |
| | Buschke Ollendorff syndrome |
| | Bustos Simosa Pinto Cisternas syndrome |
| | Butyrylcholinesterase deficiency |
| |