| Disease | | Inh | | Gene Mutation | | Clinical Findings |
| Acrodermatitis Enteropathica | | AR | | SLC39A4 | | Scaly eczematous plaques over the perioral, perineal, and acral areas (hands/feet) |
| AEC Syndrome (Hay-Wells Syndrome) | | AD | | P63 (p63 protein) | | Erosive scalp dermatitis, 80% cleft lip/palate, ankyloblepharon, hypotrichosis |
| Albinism, Oculocutaneous Type 1 | | AR | | TYR (tyrosinase) | | Severe nystagmus, ↑ SCC risk, pink nevi |
| Albinism, Oculocutaneous Type 2 | | AR | | P (P protein) | | Nystagmus, light brown hair, pigmented nevi |
| Albinism, Oculocutaneous Type 3 | | AR | | TRP-1 (tyrosine-related protein) | | Nystagmus, blue/brown iris, light brown hair/skin |
| Albright Hereditary Osteodystrophy | | AD | | GNAS1 (encodes α subunit for stimulatory G protein of adenylate cyclase: Gs) | | Pseudohypoparathyroidism, short stature, shortened fourth metacarpal, soft tissue calcification and ossification (i.e., osteoma cutis) |
| Alkaptonuria | | AR | | HGD (homogentisate oxidase) | | Dark urine on standing, ochronosis, valvular heart disease, arthritis, renal calculi, red-black ear wax |
| Ataxia-Telangiectasia (Louis-Bar Syndrome) | | AR | | ATM (ataxia- telangiectasia mutated: chromosomal strand break repair) | | ↑ Leukemia/lymphoma, ↑ sensitivity to ionizing radiation, ↑ sinopulmonary infections, progressive ataxia, telangiectasias |
| Atrichia with Papules (Congenital Atrichia with Papules) | | AR | | HR (hairless gene: zinc finger) | | Normal hair at birth but not replaced after hair sheds, follicular papules (± resembles keratosis pilaris) |
| Bannayan–Riley– Ruvalcaba Syndrome | | AD | | PTEN (tumor suppressor gene) | | Macrocephaly, lipomas, hemangiomas, genital lentigines, trichilemmomas, ↑ breast/thyroid/GI cancer (CA) |
| Bazex Syndrome (Bazex-Dupre-Christol) | | XLD | | Unknown (gene linked to Xq24–q27) | | Multiple BCCs, hypotrichosis, hypohidrosis, follicular atrophoderma (circumscribed areas on dorsal hands/feet) |
| Beare-Stevenson Cutis Gyrata Syndrome | | AD | | FGFR2 (fibroblast growth factor receptor 2) | | Cutis gyrata, acanthosis nigricans, craniosynostosis (premature fusion of certain bones in skull) |
| Beckwith–Wiedemann Syndrome | | AD(<15%) | | CDKN1C (cyclindependent kinase inhibitor 1c, aka p57, or Kip2) | | Macroglossia, circular depression (helices of ears), gigantism, midline abdominal wall defects, neonatal hypoglycemia, organomegaly, ↑ Wilms tumor |
| Berardinelli-Seip Syndrome (Congenital Generalized Lipodystrophy) | | AR | | BSCL2 | | Acanthosis nigricans, type 2 diabetes mellitus, generalized lipodystrophy |
| Birt–Hogg–Dubé Syndrome | | AD | | FLCN (folliculin) | | ↑ Fibrofolliculomas, trichodiscomas, lipomas, ↑ CA (renal/colon/medullary thyroid), lung cysts |
| Björnstad Syndrome | | AR,AD | | BCS1L | | Deafness, pili torti |
| Bloom Syndrome | | AR | | BLM (RECQL3: DNA helicase) | | Oral SCC, leukemia/lymphoma, GI CA, ↑ infections, poikiloderma, photosensitivity, hypogonadism |
| Brooke–Spiegler Syndrome | | AD | | CYLD (cylindromatosis) | | Multiple trichoepitheliomas, cylindromas, spiradenomas, ± BCCs |
| Bruton Agammaglobulinemia | | XLR | | BTK (Bruton tyrosine kinase) | | ↓ B cells with ↓ Ig levels, eczema resembling atopic dermatitis, recurrent bacterial infections like impetigo/ furunculosis (especially from encapsulated organisms) |
| Buschke–Ollendorf Syndrome | | AD | | LEMD3 | | Osteopoikilosis, connective tissue nevi (dermatofibrosis lenticularis disseminata) |
| Carney Complex (LAMB Syndrome) (NAME Syndrome) | | AD | | PRKAR1 α (protein kinase c-AMP-dependent regulatory type 1 α) | | Psammomatous schwannomas, thyroid disease, multiple lentigines, blue nevi, testicular tumors, cutaneous and cardiac myxomas |
| Chédiak–Higashi Syndrome | | AR | | LYST1 (lysosomal transport) | | Oculocutaneous albinism, ataxia, giant lysosomal granules, muscle weakness |
| CHILD syndrome (Congenital Hemidysplasia with Ichthyosiform Erythroderma and Limb Defects) | | XLD | | EBP gene (emopamil binding protein) | | Unilateral ichthyosiform erythroderma, limb/visceral hypoplasia, stippled epiphyses |
| Chondrodysplasia Punctata | | XLR | | Arysulfatase E | | Ichthyosis, sparse hair, stippled epiphyses (punctate chondral calcifications) |
| Chondrodysplasia Punctata, Rhizomelic | | AR | | PEX7 (peroxisomal biogenesis disorder) | | Stippled epiphyses, accumulation of phytanic acid, follicular atrophoderma, scarring alopecia, cataracts, rhizomelia (striking shortening of proximal limbs) |
| Chondrodysplasia Punctate, XLD (Conradi–Hünermann–Happle Syndrome) | | XLD | | EBP (emopamil-binding protein) | | Ichthyosiform erythroderma (along lines of Blaschko), follicular atrophoderma, patchy alopecia, cataracts, stippled epiphyses |
| Chronic Granulomatous Disease | | XLR (mostly) | | CYBB (cytochrome B, b subunit → phagocyte NADPH oxidase defect, so unable to deliver respiratory burst for catalase-positive bacteria) | | Recurrent infections, initially with staph infections around ears/nose, lymphadenopathy, cutaneous abscesses, suppurative lymphadenitis |
| Citrullinemia | | AD | | ASS (argininosuccinate synthetase, in urea cycle) | | Lethargy, poor feeding, seizures, vomiting |
| Cockayne Syndrome | | AR | | ERCC8 (CSA)
ERCC6 (CSB) | | Premature aging, cataracts, cachectic dwarfism, retinitis pigmentosa, ERCC6 (CSB) photosensitivity |
| Congenital Contractural Arachnodactyly | | AD | | FBN2 (fibrillin-2) | | Crumpled ears, arachnodactyly, long limbs, scoliosis |
| Congenital Ichthyosiform Erythroderma (Nonbullous CIE) | | AR | | TGM1 (transglutaminase-1)
ALOX12B (lipoxygenase)
ALOXE3 (lipoxygenase) | | Collodion membrane, generalized erythroderma with fine scaling (flexural involvement), palmoplantar keratoderma (PPK) |
| Cowden Syndrome (Multiple Hamartoma Syndrome) | | AD | | PTEN (tumor suppressor gene) | | Trichilemmomas, oral papillomas, ↑ CA (breast, thyroid follicular, colon), fibrocystic breast changes, cobblestoning of mucosa |
| Cutis Laxa | | AR | | FBLN5 (fibulin 5) | | Loose pendulous skin with decreased elasticity, diverticulae (bladder/GI), pulmonary emphysema, pulmonary artery stenosis |
| Cutis Laxa | | AD | | ELN (elastin), FBLN5 | | Loose pendulous skin, systemic involvement uncommon |
| Cutis Laxa (Occipital Horn Syndrome, EDS IX) | | XLR | | ATP7A (copper transport disease) | | Mild skin laxity, skeletal malformations, GU tract abnormalities, joint laxity |
| Darier Disease (Darier–White Disease) (Keratosis Follicularis) | | AD | | SERCA2 (calcium-dependent ATPase 2A2) | | Acrokeratosis verruciformis, warty papules/plaques in seborrheic distribution, red/white longitudinal streaking of nails with v-shaped nicks at free margin |
| Dyskeratosis Congenita (Zinsser-Engman-Cole Syndrome) | | XLR | | DKC1 (dyskerin: ribosome assembly chaperone) | | Reticulate gray brown hyperpigmentation, dystrophic nails, alopecia, premalignant leukoplakia, pancytopenia, continuous lacrimation, ↑ malignancy |
| | AD | | TERC (telomerase RNA component) | |
| EB Recessive Dystrophic (RDEB-HS) (Hallopeau-Siemens) | | AR | | Type VII collagen (premature termination codon) | | Severe widespread bullae at birth, scarring on hands/feet (mitten deformity), nail dystrophy, mucosal strictures, ↑ oral/ esophageal/skin SCCs |
| EB, Dominant Dystrophic (DDEB) (Cockayne-Touraine) | | AD | | Type VII collagen (anchoring fibrils) | | Bullae mainly over extremities, nail dystrophy, less severe than RDEB |
| EB Simplex (Dowling-Meara) | | AD | | K5/14 (EM: clumped tonofilaments in basal layer) | | Herpetiform bullae, early death, PPK, nail dystrophy, mucosal involvment (laryngeal, esophageal) |
| EB Simplex (EBS) (Weber-Cockayne) (Localized) | | AD | | K5/14 (keratin) | | Onset in childhood, bullae mainly in extremities (hands, feet), heals without scarring |
| EBS with Muscular Dystrophy | | AR | | Plectin (hemidesmosome) | | Muscular (myotonic) dystrophy, widespread bullae at birth, scarring, early death |
| EB Junctional (JEB) (Herlitz) (EB Lethalis) | | AR | | LAMA3 (subunit of laminin 5, now called laminin 332) (premature termination codon) | | Widespread bullae, exuberant perioral granulation tissue, early death, enamel defects, severe mucosal involvement (respiratory/GI tract), ± hoarseness |
| EB Junctional (Non-Herlitz) (Generalized Atrophic Benign EB) | | AR | | Laminin 332 (5) or BPAG2 | | Bullae, mild oral involvement, scarring alopecia, improves over time |
| EB Junctional with Pyloric Atresia | | AR | | α 6 β 4 (integrin) | | Bullae, pyloric atresia, hydronephrosis, mucosal erosions |
| Ectodermal Dysplasia with Skin Fragility | | AD | | Plakophilin 1 and 2 (mainly) | | Fragile bullae and erosions/crust, perioral fissuring and cheilits, PPK, nail dystrophy |
| EEC Syndrome (Ectrodactyly, Ectodermal Dysplasia, Cleft Lip/Palate) | | AD | | p63 gene | | Cleft lip/palate, ectodermal dysplasia, ectrodactyly (absence of one or more central digits of hand or foot, also called ‘lobster claw deformity’) |
| Epidermodysplasia Verruciformis | | AR | | EVER1, EVER2 | | Abnormal susceptibility to human papillomaviruses of the skin (often HPV 5/8/47), ↑ SCCs |
| Epidermolytic Hyperkeratosis (Generalized EHK) (Bullous CIE) | | AD | | K1, K10 (clumping of keratin filaments in suprabasal layers) | | Erythema/blistering in infancy and replaced by hyperkeratosis (flexural predominance) |
| Erythrokeratodermia Variabilis (Mendes da Costa) | | AD (mainly) | | GJB3 and GJB4 (connexin 31 and 30.3) | | Transient erythematous figurate patches, fixed hyperkeratotic plaques |
| Fabry Disease (Angiokeratoma Corporis Diffusum) | | XLR | | α -Galactosidase A | | Angiokeratomas, pain/paresthesia of limbs, whorled corneal opacities, hypohidrosis, renal and coronary insufficiency, “maltese crosses” (birefringent lipids in urine) |
| Familial Mediterranean Fever (FMF) | | AR | | MEFV (pyrin, also known as marenostrin) | | Recurrent febrile episodes with self-limited but painful episodes of synovitis, peritonitis, pleuritis |
| Familial Partial Lipodystrophy (FPLD) | | AD | | LMNA (lamins A and C) | | Absence of subcutaneous fat, muscular appearing arms/legs, acanthosis nigricans, diabetes mellitus |
| Focal Dermal Hypoplasia (Goltz Syndrome) | | XLD | | POCRN (X chromosome: encodes acyltransferase) | | Alopecia, fat herniation, osteopathia striata, mucocutaneous papillomas, and enamel pits |
| Gardner Syndrome (Familial Polyposis of the Colon) | | AD | | APC (adenomatosis polyposis coli) | | GI polyps, ↑ colon cancer, osteomas (jaw), supernumerary teeth, epidermoid cysts, CHRPE (congenital hypertrophy retinal pigment epithelium) |
| Gaucher Disease | | AR | | β-Glucosidase (also known as glucocerebrosidase) | | Erlenmeyer flask bone deformity, bone pain, aseptic necrosis, hepatosplenomegaly, ± CNS involvement |
| Gorlin Syndrome (Nevoid BCC Syndrome) (Basal Cell Nevus Syndrome) | | AD | | PTCH (patched mutation → SMO activation [Hedgehog pathway] resulting in ↑ Gli) | | Palmoplantar pits, jaw cysts, bifid ribs, ovarian fibromas, medulloblastomas, falx calcification |
| Griscelli Syndrome | | AR | | Rab 27A
MyO5A (myosin V) | | Pancytopenia, immunodeficiency, silvery gray hair, partial albinism, ↑ infections, neurological impairment |
| Hailey–Hailey Disease (Familial Benign Chronic Pemphigus) | | AD | | ATP2C1 (golgi-associated Ca2+ ATPase, interferes with intracellular calcium signaling) | | Flaccid blisters and erosions in intertriginous areas with vegetating plaques |
| Haim–Munk Syndrome | | AR | | Cathepsin C | | Erythematous PPK, onychogryphosis, periodontitis, early loss of teeth, acroosteolysis |
| Harlequin Fetus | | AR | | ABCA12 | | Restrictive plate-like scales, eclabium, death due to respiratory difficulty and/or sepsis |
| Hartnup Disease | | AR | | SLC6A19 (defective intestinal/renal neutral amino acid transport) | | Pellagra-like dermatosis with photosensitivity, ataxia, tremors |
| Hereditary Angioedema | | AD | | SERPING1 (gene for C1-INH, serine protease inhibitor) | | Episodes of nonpitting swelling (angioedema), ± abdominal pain, diarrhea, paroxysmal colicky pain |
| Hereditary Congenital Lymphedema (Nonne-Milroy) | | AD | | VEGFR3 (FLT4) | | Congenital lymphedema, chylous ascites, bilateral pleural effusions |
| Hereditary Hemorrhagic Telangiectasia (Osler-Weber- Rendu) | | AD | | ENG (endoglin)
ACVRL1 (ALK1) | | Pulmonary and hepatic AVMs, recurrent epistaxis, visceral hemorrhages (especially ACVRL1 (ALK1) GI), telangiectasias |
| Hermansky–Pudlak Syndrome (HPS) | | AR | | HPS (lysosomal transport protein) | | Oculocutaneous albinism, no dense bodies in platelets, ↑ bleeding, granulomatous colitis, pulmonary fibrosis |
| Hidrotic Ectodermal Dysplasia (Clouston Syndrome) | | AD | | GJB6 (connexin 30: gap junction protein) | | PPK, nail dystrophy, sparse hair, patchy alopecia, normal teeth, normal sweating, tufting of the terminal phalanges |
| Holocarboxylase Synthetase Deficiency | | | | HLCS (holocarboxylase synthetase) | | Alopecia, perioral and perianal scaly dermatitis, lethargy, difficulty feeding |
| Homocystinuria | | AR | | CBS (cystathione b-synthetase) | | Marfanoid habitus, downward displaced lens (ectopia lentis), thromboembolic events, neurologic features |
| Howel–Evans Syndrome (Tylosis-Esophageal Carcinoma) | | AD | | TOC (envoplakin) | | Focal PPK over pressure areas (balls of feet > hands), oral leukokeratosis, ↑ esophageal carcinoma |
| Hunter Syndrome | | XLR | | Iduronate-2-sulfatase | | Ivory-colored papules between scapula, cardiac involvment, joint stiffness, mental retardation |
| Hurler Syndrome | | AR | | α-L-iduronidase | | No skin findings |
| Hyper-IgE Syndrome (Job Syndrome) | | AD (mainly) | | STAT3 | | Recurrent “cold” staph infections, eczema, retained primary teeth, ↑ eosinophils, ↑ IgE |
| Hypohidrotic Ectodermal Dysplasia (HED) (Anhidrotic Ectodermal Dysplasia) (Christ- Siemens-Touraine) | | XR
AD
AR | | EDA (ectodysplasin A)
EDAR (EDA receptor)
NF- κ B critical role | | Hypotrichosis, ↓↓ sweating with heat intolerance, periorbital hyperpigmentation, peg-shaped teeth, anodontia, normal nails, saddle facies with large lips |
| Hypohidrotic ED with Immunodeficiency (HED-ID) | | XLR | | NEMO (encodes protein nuclear factor NF- κ B essential modulator) | | Hypohidrotic ED, immune system abnormalities |
| Ichthyosis Bullosa of Siemens | | AD | | K2E (keratin 2e) | | Hyperkeratotic ridged plaques in flexural areas; tonofilament clumping (upper spinous/granular layers on EM) |
| Ichthyosis, Lamellar (LI) | | AR | | TGM1 (transglutaminase 1) | | Collodion membrane, plate-like scales, eclabium, ectropion (± incomplete lid closure with subsequent keratitis) |
| Ichthyosis, X-linked (XLI) (Steroid Sulfatase Deficiency) | | XLR | | STS (steroid sulfatase) | | Corneal opacities, cryptorchidism, testicular cancer, polygonal brown scales (invariably on the neck) |
| Ichthyosis, Vulgaris | | AD | | FLG (filaggrin) | | Dry skin with scaling (extensor extremities mainly) |
| Incontinentia Pigmenti (Bloch-Sulzberger Syndrome) | | XLD | | NEMO (nuclear factor NF- κ B essential modulator) | | Peg-shaped teeth, eye abnormalities, alopecia, four stages (vesicular, verrucous, hyperpigmented, hypopigmented) |
| Kindler Syndrome | | AR, AD | | KIND1 (kindlin-1) | | Congenital blistering and photosensitivity, poikiloderma with cutaneous atrophy, PPK |
| KID Syndrome (Keratitis-Ichthyosis-Deafness Syndrome) | | AD mainly sporadic | | GJB2 (connexin 26) | | Vascularizing keratitis, night blindness, PPK, photophobia, deafness, ichthyosis, symmetric hyperkeratotic ridged plaques (knees, elbows, face) |
| Leiomyomatosis (Reed Syndrome) | | AD | | FH (fumarate hydratase) | | Cutaneous and uterine leiomyomas, renal cysts, renal cell cancer |
| LEOPARD Syndrome | | AD | | PTPN11 (protein tyrosine phosphatase non-receptor type 11) | | Lentigines, ECG defects, ocular hypertelorism, pulmonic stenosis, abnormal genitalia, retarded growth, deafness |
| Lesch–Nyhan Syndrome | | XLR | | HGPRT (hypoxanthine-guanine phosphoribosyltransferase) | | Hyperuricemia, self-mutilation, neurologic dysfunction, gout-like arthritis |
| Lhermitte–Duclos Syndrome (Dysplastic Gangliocytoma of the Cerebellum) | | AD (if with Cowden) | | PTEN (tumor suppressor gene) | | Slowly enlarging mass within cerebellar cortex, cerebellar signs, ↑ intracranial pressure, often associated with Cowden syndrome |
| Li–Fraumeni Syndrome | | AD | | P53 (tumor suppressor gene) | | ↑ Breast CA, ↑ brain tumors, ↑ osteosarcoma, ↑ leukemia (skin cancer not typical feature) |
| Lipoid Proteinosis (Urbach-Wiethe Disease) | | AR | | ECM1 (extracellular matrix protein 1) | | Waxy yellow papules on face, thick tongue, hoarse cry, hippocampal calcifications, alopecia, row of beaded papules along eyelid margin (string of pearls) |
| Lymphedema-Distichiasis Syndrome | | AD | | FOXC2 (forkhead box protein C2: transcription factor) | | Lower-limb lymphedema starting in late childhood, distichiasis (double row of eyelashes) |
| Maffucci Syndrome | | Sporadic | | Maybe PTHR1 (parathyroid hormone receptor type 1) | | Venous malformations of distal extremities, endochrondromas, chondrosarcomas |
| Mal de Meleda | | AR | | SLURP1 (encodes protein: s ecreted Ly-6/uPar related protein) | | Transgredient PPK (hands, feet, elbows, knees), hyperhidrosis with malodor and secondary infections, perioral erythema |
| McCune–Albright Syndrome (Polyostotic Fibrodysplasia) | | Sporadic | | GNAS1 (α subunit of stimulatory G protein, Gs, of adenylate cyclase) | | Precocious puberty, endocrine hyperfunction, large café-au-lait pigmentation (“coast of Maine”), fibrous dysplasia of bones (may lead to pathological fractures) |
| MEN 1 (Wermer Syndrome) | | AD | | MEN1 (menin: tumor suppressor gene) | | Tumors (parathyroid, pituitary, pancreatic), collagenomas, lipomas, multiple angiofi- bromas (occurs later than in tuberous sclerosis) |
| MEN 2a (Sipple syndrome) | | AD | | RET (renin protooncogene: tyrosine kinase receptor) | | Macular amyloidosis, hyperparathyroidism, medullary thyroid carcinoma, pheochromocytoma |
| MEN 2b | | AD | | RET (renin proto-oncogene: tyrosine kinase receptor) | | Mucosal neuromas with thickened lips, marfanoid habitus, medullary thyroid carcinoma, pheochromocytoma, GI problems (i.e., diverticulosis) |
| Menkes Disease (Menkes Kinky Hair Disease) | | XLR | | MNK (also known as ATP7a, copper transporting ATPase) | | Doughy skin, sparse short hair, pili torti, seizures, growth failure, hypotonia, mental retardation |
| MIDAS Syndrome | | XLD | | HCCS (Holocytochrome c-type synthase) | | Microphthalmia, dermal aplasia, sclerocornea, ± cardiac arrhythmias |
| Monilethrix (Beaded Hair) | | AD | | K86, K81 (human hair keratin: hHb6 and hHb1) | | Normal hair at birth → fragile, brittle short hair first few months later, keratosis pilaris, monilethrix (hair fibers with elliptical nodes alternating with abnormal constrictions) |
| Muckle–Wells Syndrome (Urticaria- Deafness-Amyloidosis) | | AD | | CIAS1 (cryopryin) | | Episodic fevers, lancinating limb pain, urticaria-like eruption, progressive deafness, ± amyloidosis (AA) |
| Muir–Torre Syndrome | | AD | | MSH2, MLH1, MSH6 (DNA mismatch repair genes) | | Sebaceous adenomas and carcinomas, keratoacanthomas, colon cancer |
| Nail–Patella Syndrome (Hereditary Osteo- Onychodysplasia) (HOOD) | | AD | | LMX1B (transcription factor that regulates collagen synthesis) | | Triangular lunulae, hypoplastic nails, absent patella, scapular thickening, Lester iris, radial head abnormalities, iliac crest exostoses |
| Naxos Disease | | AR | | Plakoglobin (cell adhesion protein) | | Woolly hair, diffuse PPK, right ventricular cardiomyopathy and arrhythmia |
| Neimann–Pick Disease | | AR | | SMPD1 (sphingomyelinase) | | Hepatosplenomegaly, thrombocytopenia, ataxia, dysarthria, dystonia, seizures |
| Netherton Syndrome | | AR | | SPINK5 (LEKTI: serine protease) | | Ichthyosiform linearis circumflexa, atopic dermatitis, trichorrhexis invaginata |
| Neurofibromatosis I (Von Recklinghausen Disease) | | AD | | NF1 (neurofibromin: tumor suppressor gene) | | Lisch nodules, neurofibromas, café-au-lait macules, axillary/inguinal freckling, ± learning disabilities, ↑ tumors (i.e., optic gliomas, malignant peripheral nerve sheath tumors, CNS tumors, juvenile myelomonocytic leukemia) |
| Neurofibromatosis II | | AD | | NF2 (schwannomin, also known as merlin) | | CALMs, noncancerous tumors of nervous system (acoustic neuromas, meningiomas, spinal tumors) |
| Noonan Syndrome | | AD | | PTPN11 (protein tyrosine phosphatase SHP-2), KRAS, RAF1, SOS1 | | Lymphedema, keloids, edema over hands/feet, poor tongue control, low-set ears, hypertelorism, low-set hairline at nape of neck, webbed neck, short stature |
| Occipital Horn Syndrome [(X-linked Cutis Laxa) formerly known as EDS variant] | | XLR | | ATP7A (copper transporting ATPase) | | Skin and joint laxity, pili torti, vascular tortuosity, occipital horns (bilateral occipital exostoses of the skull) |
| Pachyonychia Congenita, Type I (Jadassohn-Lewandowsky) | | AD | | K6, K16 (Type 1) | | Focal PPK, benign oral leukokeratosis, nail dystrophy (significant subungual hyperkeratosis) |
| Pachyonychia Congenita, Type II (Jackson-Lawler) | | AD | | K6b, K17 (Type 2) | | Nail dystrophy, steatocystomas, eruptive vellus hair cysts, natal teeth, pili torti |
| PAPA Syndrome | | AD | | CD2BP1 (CD2 binding protein 1) | | Pyogenic arthritis, pyoderma gangrenosum, acne |
| Papillon–Lefèvre Syndrome | | AR | | CTSC (cathepsin C) | | Stocking glove PPK, periodontitis, premature tooth loss, dural calcifications |
| Peutz–Jeghers Syndrome | | AD | | STK11 (known as LKB1, serine/threonine kinase 11) | | Periororal, intraoral and acral lentigines, GI polyps (mainly hamartomatous, not premalignant) |
| Phenylketonuria | | AR | | PAH (phenylalanine hydroxylase) | | Pigmentary dilution (blonde, blue eyes), eczematous dermatitis, seizures, mental retardation, mousy odor |
| PIBIDS | | AR | | ERCC2/XPD (nucleotide excision repair) | | Photosensitivity, ichthyosis, brittle hair, infertility, developmental delay, short stature |
| Piebaldism | | AD | | KIT (proto-oncogene) (defect in migration/ differentiation of melanoblasts from neural crest) | | Poliosis (↓ or absence of melanin in scalp hair or eyelashes) often with white forelock, focal areas of leukoderma |
| Porphyria Cutanea Tarda (Familial Porphyria Cutanea Tarda) | | AD | | UROD (uroporphyrinogen decarboxylase) | | Cutaneous fragility of sun-exposed sites (bullae, erosions, milia, atrophic scars), temporal/malar hypertrichosis, indurated plaques on chest/back |
| Porphyria, Congenital Erythropoietic (Gunther) | | AR | | UROS (uroporphyrinogen III cosynthase) | | PCT cutaneous findings (often more severe), hemolysis, erythrodontia, infections, hematologic complications |
| Porphyria, Hereditary Coproporphyria | | AD | | CPO (coproporphyrinogen oxidase) | | Dark urine, photosensitivity, PCT cutaneous findings, episodic attacks of abdominal pain, ± CNS changes |
| Porphyria, Variegate | | AD | | PPO (protoporphyrinogen oxidase) | | PCT cutaneous findings, neuropsychiatric symptoms |
| Porphyria, Acute Intermittent | | AD | | PBD (porphobilinogen deaminase) | | No skin manifestation |
| Porphyria, Erythropoietic Protoporphyria | | AD | | Ferrochelatase | | Photosensitivity with stinging, wax-like scarring, cholestasis, ± liver damage |
| Progeria (Hutchinson–Gilford syndrome) | | | | LMNA (nuclear lamins A and C) | | Premature aging, prominent scalp veins, beaked nose, scleroderma-like skin, short stature, alopecia, atherosclerosis, premature death |
| Pseudoxanthoma Elasticum | | AR | | ABCC6 (ABC cassette transporter MRP6) | | Small yellow papules, cutaneous laxity (neck, axilla, groin), angioid streaks, calcification of elastic fibers (claudication, myocardial infarction) |
| Refsum Syndrome | | AR | | PHYH (PAHX) or PEX7 (↓ peroxisomal enzyme: phytanoyl CoA hydroxylase) | | Retinitis pigmentosa, deafness, peripheral neuropathy, mild ichthyosis, cerebellar ataxia |
| Richner-Hanhart Syndrome | | AR | | TAT (hepatic tyrosine aminotransferase) | | Pseudoherpetic keratitis, painful focal PPK |
| Rombo Syndrome | | AD | | Unknown | | Atrophoderma vermiculatum, BCCs, hypotrichosis |
| Rothmund–Thomson Syndrome (Poikiloderma Congenitale) | | AR | | RECQL4 (DNA helicase) | | Photosensitivity, absent radii, hypoplastic thumbs, premalignant acral keratoses, cataracts, alopecia, nail dystrophy,↑ osteosarcoma and SCC |
| Rubinstein–Taybi Syndrome | | Sporadic mainly | | CBP (CREB binding protein) | | Heart defects, beaked nose, broad thumbs, capillary malformations, multiple pilomatricomas, keloids, short stature, mental retardation |
| Sjögren–Larsson Syndrome | | AR | | FALDH (fatty aldehyde dehydrogenase, aka ALDH3A2) | | Ichthyosis, persistent pruritus, mental retardation, epilepsy, spastic di- or tetraplegia, glistening white perifoveal dots in ocular fundus |
| Trichorhinophalangeal Syndrome | | Sporadic or AD | | TRPS-1 | | Bullous pear-shaped nose, shortened phalanges, brachydactyly, cone-shaped epiphyses |
| Tuberous Sclerosis | | AD | | TSC1 (hamartin gene)
TSC2 (tuberin gene) | | Facial angiofibromas, ash-leaf macules, seizures, shagreen patch, periungual and gingival fibromas, dental enamel pits, neuropsychiatric defects |
| Uncombable Syndrome (Pili Trianguli Et Canaliculi) | | Sporadic or AD | | Unknown | | Stiff hair with “spun glass” appearance and difficult to comb, triangular shaped shaft (longitudinal groove) |
| Vohwinkel, Classic (Mutilating PPK) | | AD | | GJB2 (connexin 26) | | Ichthyosis, deafness, starfish-shaped keratotic plaques, pseudoainhum, honeycomb PPK |
| Vohwinkel, Variant | | AD | | Loricrin | | Ichthyotic variant, no deafness |
| Waardenburg Syndrome | | AD | | PAX3 (transcription factor) MITF, SOX10 | | Dystopia canthorum, white forelock, heterochromia of the eyes, deafness, synophrys |
| Werner Syndrome (Adult Progeria) | | AR | | WRN (also known as RECQL2: DNA helicase) | | Sclerodermoid changes, ulcerations over bony prominences, ↑ CA, premature aging (cataracts, diabetes mellitus, atherosclerosis, osteoporosis in 20s) |
| Wiskott–Aldrich Syndrome | | XLR | | WASP | | Eczema, thrombocytopenia, immune deficiency, ↑ pyogenic infections |
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