Rare Diseases

Heimler Syndrome: A Comprehensive Medical Review Introduction Heimler syndrome (also known as deafness-enamel hypoplasia-nail defects syndrome; OMIM #234580, #616617) is an ultra-rare autosomal recessive disorder characterized by the classic triad of sensorineural hearing loss, amelogenesis imperfecta (enamel hypoplasia) affecting primarily the secondary dentition, and nail abnormalities, with occasional or late-onset retinal pigmentation abnormalities. First described […]

Hecht Syndrome (Trismus-Pseudocamptodactyly Syndrome): A Comprehensive Medical Review Introduction Hecht syndrome, also known as trismus-pseudocamptodactyly syndrome (TPS) or Distal Arthrogryposis Type 7 (DA7), is a rare autosomal dominant disorder of muscle development characterized by congenital contractures of the temporomandibular joint resulting in an inability to fully open the mouth (trismus) and short muscle and tendon

Hemoglobin SC (HbSC) Disease: A Comprehensive Medical Review Introduction Hemoglobin SC disease (HbSC) is a genetic hemoglobinopathy resulting from the compound heterozygous inheritance of hemoglobin S (HbS; β6Glu→Val) and hemoglobin C (HbC; β6Glu→Lys), representing the second most common form of sickle cell disease after homozygous HbSS disease, accounting for approximately 20-30% of all sickle cell

Hemoglobin SD (HbSD) Disease: A Comprehensive Medical Review Introduction Hemoglobin SD disease (also known as HbSD Punjab, sickle cell-hemoglobin D compound heterozygosity, or HbS/D Punjab disease) is a rare genetic hemoglobinopathy characterized by the compound heterozygous inheritance of hemoglobin S (HbS) and hemoglobin D Punjab (HbD), resulting in a variant form of sickle cell disease

Hemoglobin SE (HbSE) Disease: A Comprehensive Medical Review Introduction Hemoglobin SE disease (also known as HbSE compound heterozygosity or sickle cell-hemoglobin E disease) is a rare genetic hemoglobinopathy characterized by the compound heterozygous inheritance of hemoglobin S (HbS) from one parent and hemoglobin E (HbE) from the other, resulting in a unique variant of sickle

Hemoglobin H (HbH) Disease: A Comprehensive Medical Review Introduction Hemoglobin H disease (also known as HbH disease or alpha-thalassemia intermedia) is a moderate to severe form of alpha-thalassemia characterized by the deletion or inactivation of three out of four alpha-globin genes, resulting in moderately severe hemolytic anemia, splenomegaly, and variable clinical severity. Named for the

Hay Wells Syndrome: A Comprehensive Medical Review Introduction Hay-Wells syndrome (also known as AEC syndrome or ankyloblepharon-ectodermal dysplasia-clefting syndrome; OMIM #106260) is a rare autosomal dominant ectodermal dysplasia characterized by the distinctive triad of ankyloblepharon (fusion of eyelid margins), severe ectodermal dysplasia with prominent skin erosions, and cleft lip and/or palate. First described by Hay