Humerus Trochlea Aplasia: A Comprehensive Clinical Review Introduction Humerus trochlea aplasia, also known as congenital aplasia or agenesis of the humeral trochlea, is an extremely rare familial bone deformity characterized by complete or near-complete absence of the trochlea of the humerus—the crucial articulating surface normally responsible for forming the ulnohumeral joint. This rare congenital malformation …
Hirayama Disease: A Comprehensive Clinical Review Introduction Hirayama disease (HD), also known as monomelic amyotrophy (MMA), juvenile non-progressive amyotrophy, Sobue disease, or benign monomelic amyotrophy, is a rare benign motor neuron disorder characterized by insidious onset of progressive weakness and atrophy of the distal upper limb musculature in young males, followed by spontaneous cessation of …
Hidrotic Ectodermal Dysplasia (Clouston Syndrome): A Comprehensive Review Introduction Hidrotic ectodermal dysplasia (HED), also known as Clouston syndrome or hidrotic ectodermal dysplasia type 2 (HED2), is a rare autosomal dominant genodermatosis characterized by a distinctive triad of clinical findings: partial-to-complete alopecia, nail dystrophy, and palmoplantar hyperkeratosis. Unlike the more common hypohidrotic ectodermal dysplasia (HED), which …
Heterotaxy Syndrome (Situs Ambiguous): A Comprehensive Review Key Takeaway Heterotaxy syndrome is a spectrum of laterality (left–right) defects in which thoracic and abdominal organs are abnormally arranged, typically with complex congenital heart disease and splenic anomalies (asplenia or polysplenia). Early recognition, multidisciplinary management, and lifelong follow‑up are essential because morbidity and mortality are driven by …
Hemitruncus Arteriosus: A Comprehensive Review Introduction Hemitruncus arteriosus, also known as anomalous origin of one pulmonary artery from the aorta (AOPA), is a rare congenital cardiovascular malformation in which one branch pulmonary artery (either right or left) arises anomalously from the ascending aorta while the other pulmonary artery maintains its normal origin from the main …
Hemi 3 Syndrome: A Comprehensive Review Introduction Hemi 3 syndrome is an extremely rare congenital neurodevelopmental disorder characterized by a distinctive constellation of four cardinal features: hemihypertrophy (overgrowth of one side of the body), hemihypaesthesia (decreased sensation on the affected side), hemiareflexia (absent reflexes on the affected side), and scoliosis. First described by Nudleman, Andermann, …
Heller Syndrome (Childhood Disintegrative Disorder): A Comprehensive Review Introduction Childhood Disintegrative Disorder (CDD), also known as Heller syndrome or dementia infantilis, is an extremely rare neurodevelopmental disorder characterized by a period of apparently normal development for at least two years, followed by a profound and often irreversible regression in language, social, and adaptive functioning. Originally …