Rare Diseases

Hadziselimovic Syndrome: A Comprehensive Medical Review Introduction Hadziselimovic syndrome, more formally known as microcephaly-facio-cardio-skeletal syndrome, Hadziselimovic type, is an extraordinarily rare genetic disorder characterized by a distinctive constellation of prenatal growth retardation, microcephaly, characteristic facial features, cardiac malformations, and skeletal abnormalities. First described in the medical literature, this syndrome represents one of the rarest known …

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Haddad Syndrome: A Comprehensive Medical Review Introduction Haddad syndrome, also known as Ondine-Hirschsprung syndrome or congenital central alveolar hypoventilation-Hirschsprung disease syndrome, is an extraordinarily rare congenital disorder characterized by the coexistence of congenital central hypoventilation syndrome (CCHS) and Hirschsprung disease (HD). First described by Gabriel Haddad in 1978, this syndrome represents a severe form of …

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Haberland Syndrome: A Comprehensive Review Introduction Haberland syndrome, also known as encephalocraniocutaneous lipomatosis (ECCL) or Fishman syndrome, is an extraordinarily rare congenital neurocutaneous disorder first described by Catherine Haberland and Maurice Perou in 1970. This sporadic condition affects approximately 60-70 individuals worldwide since its initial description, making it one of the rarest neurocutaneous syndromes known …

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HUPRA Syndrome: A Comprehensive Review Introduction HUPRA syndrome (Hyperuricemia, Pulmonary hypertension, Renal failure in infancy, and Alkalosis) is an ultrarare autosomal recessive mitochondrial disease first described in 2011. The condition is characterized by a distinctive constellation of clinical features that reflect severe mitochondrial dysfunction affecting multiple organ systems. With fewer than ten cases reported worldwide …

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HPRT1 Partial Deficiency (Kelley-Seegmiller Syndrome): A Comprehensive Review Introduction HPRT1 partial deficiency, commonly known as Kelley-Seegmiller syndrome, is a rare, X-linked recessive disorder of purine metabolism caused by decreased activity of the hypoxanthine-guanine phosphoribosyltransferase (HPRT) enzyme. Unlike complete HPRT deficiency (Lesch-Nyhan syndrome), this disorder presents primarily with hyperuricemia and gout, with little or no neurological …

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HPRT Complete Deficiency: A Comprehensive Medical Review Introduction HPRT complete deficiency, also known as Lesch-Nyhan syndrome (LNS), is a rare X-linked recessive inborn error of purine metabolism caused by the virtual absence or severe deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT) enzyme activity. According to trusted medical organizations including the National Organization for Rare Disorders (NORD), the …

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HOPP Syndrome: A Comprehensive Medical Review Introduction HOPP syndrome, standing for Hypotrichosis, Osteolysis, Periodontitis, and Palmoplantar keratoderma syndrome, is an extremely rare ectodermal dysplasia syndrome first described by Van Steensel and colleagues in 2002. According to trusted medical organizations including Orphanet, the National Organization for Rare Disorders (NORD), and the European Reference Networks, this condition …

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