Rare Diseases

Hartsfield Syndrome: A Comprehensive Medical Review Introduction Hartsfield syndrome (also known as Hartsfield-Bixler-Demyer syndrome or holoprosencephaly-ectrodactyly-cleft lip/palate syndrome; OMIM #300571) is an extremely rare genetic disorder characterized by the unique combination of holoprosencephaly (HPE), ectrodactyly (split hand/foot malformation), and cleft lip/palate, with variable endocrine abnormalities and developmental delays. First described by Hartsfield in 1984, the …

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Hartnup Disease: A Comprehensive Medical Review Introduction Hartnup disease (also known as Hartnup disorder or pellagra-like dermatosis) is a rare autosomal recessive metabolic disorder characterized by impaired absorption and renal reabsorption of neutral amino acids, leading to niacin (vitamin B₃) deficiency and pellagra-like manifestations. Named after the Hartnup family from England, in whom the condition …

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Harrod Syndrome: A Comprehensive Medical Review Introduction Harrod syndrome, also known as Harrod-Doman-Keele syndrome or cranio-facio-digito-genital syndrome, is an extremely rare genetic disorder characterized by a distinctive constellation of intellectual disability, craniofacial dysmorphism, skeletal abnormalities (particularly arachnodactyly), and genital anomalies. First described by Harrod, Doman, and Keele in 1984, this syndrome has been documented in …

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Harlequin Syndrome: A Comprehensive Medical Review Introduction Harlequin syndrome is a rare autonomic neurological disorder characterized by sudden onset of unilateral facial flushing and sweating, with the contralateral side remaining pale and dry. Named after the colorfully costumed Harlequin character from Commedia dell’Arte, the syndrome was first comprehensively described by Lance, Drummond, Gandevia, and Morris …

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Hardikar Syndrome: A Comprehensive Medical Review Introduction Hardikar syndrome (also known as cholestasis-pigmentary retinopathy-cleft palate syndrome) is an extremely rare X-linked dominant multiple congenital anomaly disorder characterized by a distinctive constellation of obstructive liver disease, pigmentary retinopathy, orofacial clefting, and genitourinary abnormalities. First described by Dr. Winita Hardikar and colleagues in 1992 at the Royal …

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Hardcastle Syndrome (Diaphyseal Medullary Stenosis–Bone Malignancy Syndrome): A Comprehensive Medical Review Introduction Hardcastle syndrome, also known as Diaphyseal Medullary Stenosis with Malignant Fibrous Histiocytoma (DMS-MFH), is a rare inherited skeletal dysplasia characterized by symmetric diaphyseal medullary stenosis of long bones, cortical thickening, bone fragility, and a markedly increased risk of malignant transformation, particularly malignant fibrous …

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Harboyan Syndrome: A Comprehensive Medical Review Introduction Harboyan syndrome, also known as corneal dystrophy-perceptive deafness syndrome (CDPD) or congenital hereditary endothelial dystrophy with progressive sensorineural deafness (OMIM #217400), is an extremely rare autosomal recessive genetic disorder characterized by the combination of congenital corneal endothelial dystrophy and progressive postlingual sensorineural hearing loss. First described by Harboyan …

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