L
- LBWD syndrome
- LCHAD deficiency
- LEOPARD syndrome
- Laband syndrome
- Labile diabetes
- Labyrinthitis
- Lachiewicz Sibley syndrome
- Lacrimo-auriculo-dento-digital syndrome
- Lactate dehydrogenase b deficiency
- Lactate dehydrogenase deficiency
- Lactate dehydrogenase deficiency type A
- Lactate dehydrogenase deficiency type B
- Lactate dehydrogenase deficiency type C
- Ladda Zonana Ramer syndrome
- Lafora disease
- Lagophthalmia cleft lip palate
- Laing distal myopathy
- Lambdoid synostosis
- Lambert Eaton myasthenic syndrome
- Lambert syndrome
- Lambert-Eaton Syndrome
- Lamellar ichthyosis
- Landau-Kleffner syndrome
- Landouzy-Dejerine Muscular Dystrophy
- Langer Nishino Yamaguchi syndrome
- Langer mesomelic dysplasia
- Langer mesomelic dysplasia syndrome
- Langer-Giedion Syndrome
- Langerhans cell histiocytosis
- Langerhans cell sarcoma
- Laparoschisis
- Laron syndrome
- Larsen syndrome
- Larsen-like syndrome
- Laryngeal abductor paralysis mental retardation
- Laryngeal cancer, childhood
- Laryngeal cleft
- Laryngeal papillomatosis
- Laryngeal web congenital heart disease short stature
- Laryngocele
- Laryngoonychocutaneous syndrome
- Larynx atresia
- Larynx, congenital partial atresia of
- Lassueur-Graham-Little syndrome
- Late infantile autosomal recessive myotonia
- Late-onset carnitine palmitoyltransferase II deficiency
- Late-onset congenital adrenal hyperplasia
- Late-onset multiple carboxylase deficiency
- Lateral body wall defect
- Lateral meningocele syndrome
- Laterality defects dominant
- Lathosterolosis
- Lattice corneal dystrophy type 3A
- Launois-Bensaude adenolipomatosis
- Laurence Prosser Rocker syndrome
- Laurence-Moon syndrome
- Laurence-Moon-Bardet-Biedl syndrome
- Laurin-Sandrow syndrome
- Le Marec Bracq Picaud syndrome
- Leao Ribeiro Da Silva syndrome
- Leber congenital amaurosis
- Leber congenital amaurosis type 1
- Leber congenital amaurosis type 10
- Leber congenital amaurosis type 11
- Leber congenital amaurosis type 12
- Leber congenital amaurosis type 13
- Leber congenital amaurosis type 2
- Leber congenital amaurosis type 3
- Leber congenital amaurosis type 4
- Leber congenital amaurosis type 5
- Leber congenital amaurosis type 6
- Leber congenital amaurosis type 9
- Leber hereditary optic neuropathy
- Leber hereditary optic neuropathy with dystonia
- Leber miliary aneurysm
- Leber's Disease
- Leber's optic atrophy
- Ledderhose disease
- Left Ventricular Non-Compaction Cardiomyopathy (LVNC)
- Left ventricle-aorta tunnel
- Left-sided gallbladder
- Leg absence deformity cataract
- Legg-Calve-Perthes disease
- Legionellosis
- Legius syndrome
- Leichtman Wood Rohn syndrome
- Leigh syndrome
- Leigh syndrome, French Canadian type
- Leigh's disease
- Leiomyomatosis and renal cell cancer, hereditary
- Leiomyomatosis, esophageal and vulval, with nephropathy
- Leisti Hollister Rimoin syndrome
- Lelis syndrome
- Lemierre syndrome
- Lennox-Gastaut syndrome
- Lenz Majewski hyperostotic dwarfism
- Lenz Syndrome
- Lenz microphthalmia syndrome
- Leprechaunism
- Leprechaunism syndrome
- Leprosy
- Leptospirosis
- Leri Weill dyschondrosteosis
- Leri pleonosteosis
- Lesch Nyhan syndrome
- Lesch-Nyhan Syndrome
- Lethal Kniest-like syndrome
- Lethal congenital contracture syndrome 1
- Lethal congenital contracture syndrome 2
- Lethal short limb skeletal dysplasia Al Gazali type
- Leucine-induced hypoglycemia
- Leucine-sensitive hypoglycemia of infancy
- Leucocyte adhesion defect
- Leukemia subleukemic
- Leukemia, B-cell, chronic
- Leukemia, Myeloid
- Leukemia, T-cell, chronic
- Leukemia, mast-cell
- Leukocyte adhesion deficiency type 1
- Leukodystrophy
- Leukodystrophy with oligodontia
- Leukodystrophy, dysmyelinating, and spastic paraparesis with or without dystonia
- Leukodystrophy, hypomyelinating 3
- Leukodystrophy, psuedometachromatic
- Leukoencephalitis periaxialis concentrica
- Leukoencephalopathy palmoplantar keratoderma
- Leukoencephalopathy with Brainstem and Spinal Cord Involvement and Lactate Elevation
- Leukoencephalopathy with vanishing white matter
- Leukoencephalopathy, arthritis, colitis, and hypogammaglobulinema
- Leukomelanoderma mental redardation hypotrichosis
- Leukonychia totalis
- Levo-transposition of the great arteries
- Levotransposition of the great arteries
- Levy-Hollister syndrome
- Leydig Cell Hypoplasia
- Leydig cell agenesis
- Leydig cells hypoplasia
- leukemia of ambiguous lineage