Introduction to Autosomal Dominant Diseases Autosomal dominant (AD) diseases are a fundamental category of inherited disorders characterised by the presence of a mutant allele in just one copy of a gene. This mode of inheritance requires only a single pathogenic variant from one parent to manifest disease, making it essential knowledge for clinicians, especially within the UK setting where a multitude of AD disorders present in routine and emergency clinical practice. This article condenses key clinical lessons, diagnostic pathways, and management principles for AD diseases, focusing particularly on the well-known “CATCH Wilson” mnemonic a strategic approach to commonly encountered autosomal…
Author: Dr Ben
Introduction to Pedigree ChartsA pedigree chart is a graphical representation of a family tree that illustrates the occurrence and appearance of phenotypes of a particular gene or organism and its ancestors. It is an essential tool used in genetics, medicine, and anthropology to track the inheritance patterns of traits, diseases, and genetic conditions through generations. Understanding the key points of pedigree charts enables professionals and students alike to interpret genetic information correctly and make informed decisions.Purpose and Importance of Pedigree ChartsPedigree charts serve multiple important functions in both research and clinical settings:Tracking Genetic Disorders: They help identify inherited conditions like…
Master gestational diabetes management with key insights for PLAB candidates to boost clinical skills and exam readiness.
Introduction to PLAB Genetics QuestionsThe Professional and Linguistic Assessments Board (PLAB) test evaluates the competency of international medical graduates who wish to practice medicine in the UK. Genetics is a significant topic area within the PLAB syllabus, reflecting its importance in clinical diagnosis and patient management. This article provides an authoritative guide on practicing PLAB genetics questions, offering practical approaches, common question types, and study techniques to help candidates excel.Understanding the Core Genetics Topics in PLABBefore diving into question practice, it is crucial to understand the fundamental topics likely to be tested. These typically include:Mendelian inheritance patterns (autosomal dominant, autosomal…
Introduction to Genetic Diseases for PLAB 1 PreparationGenetic diseases form a significant part of the PLAB 1 syllabus. Understanding these conditions thoroughly is essential, as they frequently appear in clinical questions and scenarios. This article provides a concise yet comprehensive review of common genetic diseases, key inheritance patterns, clinical features, diagnostic clues, and management essentials. Memorizing these points will aid in quick recall during exam conditions.PLAB 1 exams test your understanding of fundamental medical concepts, including genetic disorders that affect patient care across all specialties. Building a strong knowledge foundation on these conditions ensures you confidently approach related multiple-choice questions,…
Understand autosomal dominant, recessive, and X-linked inheritance for better diagnosis and genetic counseling.
Definition Erythema Multiforme (EM): an acute, immune-mediated skin reaction characterized by target lesions. Often self-limiting but can be recurrent. Two main types: EM Minor: limited skin involvement, no mucosal lesions EM Major: mucosal involvement ± systemic symptoms; overlaps with Stevens-Johnson Syndrome Epidemiology & Risk Factors Peak incidence: young adults (20–40 years) Slight male predominance Common triggers: Infections (most common): HSV (herpes simplex virus), Mycoplasma pneumoniae Medications (less common): sulfonamides, NSAIDs, anticonvulsants Vaccinations or idiopathic Clinical Features Feature Description High-Yield Points Skin lesions Target (iris) lesions: concentric rings with central dusky area, raised border, erythematous halo Classic lesion = targetoid papule…
Definition Tinea infections (dermatophytoses): superficial fungal infections caused by Trichophyton, Microsporum, and Epidermophyton species. Classified by body site: Tinea capitis – scalp Tinea corporis – body (excluding scalp, groin, feet, nails) Tinea cruris – groin (“jock itch”) Epidemiology & Risk Factors Type Age/Population Risk Factors Tinea capitis Children 3–7 years Crowded settings, poor hygiene, close contact, African descent at higher risk Tinea corporis All ages Warm, humid climate, contact with infected person or animal Tinea cruris Adults, mostly males Obesity, sweating, tight clothing, diabetes, immunosuppression Clinical Features Feature Tinea Capitis Tinea Corporis Tinea Cruris Lesion Scaly patches, alopecia, broken hairs,…
Definition Impetigo: superficial bacterial skin infection, commonly affecting children. Characterized by pustules, vesicles, or honey-colored crusts, usually on the face or extremities. Highly contagious via direct contact or fomites. Epidemiology & Risk Factors Most common in children aged 2–5 years, but can occur at any age. More common in hot, humid climates. Risk factors: Minor skin trauma (scratches, insect bites) Pre-existing eczema or dermatitis Crowded living conditions Poor hygiene Etiology Staphylococcus aureus – most common cause Streptococcus pyogenes (Group A Streptococcus) Mixed infections possible Clinical Features Feature Description High-Yield Points Lesion type Vesicles, pustules, or bullae; ruptures to form honey-colored…
Definition Folliculitis: inflammation of the hair follicles, usually due to infection, irritation, or obstruction. Typically presents as small, erythematous papules or pustules centered on hair follicles. Epidemiology & Risk Factors Common in all age groups; more frequent in adults. Risk factors: Bacterial infection (most commonly Staphylococcus aureus) Occlusive clothing, friction, sweating Hot tubs or swimming pools (Pseudomonas aeruginosa) Immunosuppression or diabetes Clinical Features Feature Description High-Yield Points Lesions Small, erythematous papules or pustules Centered on hair follicle; may have hair in center Distribution Can occur anywhere with hair; commonly beard, scalp, chest, back, thighs Hot tub folliculitis: trunk and buttocks…
Overview Both acne vulgaris and rosacea are common facial skin conditions but have distinct etiologies, age groups, and treatments. Recognising differences is essential for diagnosis and PLAB-style vignettes. Comparison Table Feature Acne Vulgaris Rosacea Etiology Follicular hyperkeratinization + Propionibacterium acnes inflammation Chronic inflammatory disorder; dysregulation of innate immunity and vascular reactivity; triggers include UV, heat, alcohol, spicy food Age group Adolescents (12–25 years) Adults 30–50 years Distribution Face (T-zone), chest, back Central face: cheeks, nose, forehead, chin Lesion type Comedones (open/closed), papules, pustules, cysts Papules, pustules, erythema, telangiectasia; no comedones Triggers Hormonal changes, oily skin, cosmetics Sun, heat, alcohol, spicy…
Definition Molluscum contagiosum (MC): a benign, self-limiting viral skin infection caused by molluscum contagiosum virus (MCV), a poxvirus. Characterized by small, flesh-colored, dome-shaped papules with central umbilication. Epidemiology & Risk Factors Common in children aged 1–10 years, sexually active adults, and immunocompromised patients (e.g., HIV). Highly contagious via direct skin-to-skin contact or fomites (towels, clothing). Incubation period: 2–8 weeks. Clinical Features Feature Description High-Yield Points Lesions 2–5 mm, firm, dome-shaped, pearly/flesh-colored papules Central umbilication is characteristic Distribution Children: face, trunk, limbs; Adults: genital area (sexually transmitted) Linear arrangement may indicate autoinoculation Number Often multiple; may coalesce Can be a clue…