Term | Definition |
Oculocutaneous albinism | decreased melanin
poor vision |
Oculocutaneous albinism | OCA1: tyrosinase
OCA2: P protein gene (2.7kb deletion in AA pts)
OCA3: TYRP1 -rufous-AA
OCA4: MATP |
Hemansky-Pudlak (albinism) | abnormal platelets |
Hemansky-Pudlak (albinism) | HPS1 in Puerto Rican
HPS3 in Puerto Rican and AJ |
Chediak-Higashi (albinism) | immunodeficiency
bleeding
lymphoproliferative disorder |
Chediak-Higashi (albinism) | LYST gene |
Ocular (albinism) | poor vision
normal skin |
Ocular (albinism) | XLR
GPR143 |
Ectodermal Dysplasia (hypohidrotic) | Sparse hair, abnormal teeth, reduced sweating |
Ectodermal Dysplasia (hypohidrotic) | XLR: EDA gene
AR: EDAR and EDARADD |
Ectodermal Dysplasia (hydrotic) | sparse hair, abnormal nails, palmoplantar hyperkeratosis |
Ectodermal Dysplasia (hydrotic) | GJB6 |
Incontinentia Pigmenti | Streaky hyperpigmentation (erythema, vesicular verrucous phases)
abnormal teeth and hair;
neovascularization of retina;
neurological problems (szs, DD) |
Incontinentia Pigmenti | XLD male lethal
IKBKG gene
80% deletion |
Ichthyosis | AR congenital (collodion baby)
milder form - erythema and lamellar |
Ichthyosis | multiple genes
TGM1 (50-60%) |
Epidermolysis Bullosum | blistering of skin;
dystrophic - with scarring - blistering below basement of membrane
simplex - non-scarring - blistering above basement of membrane |
Epidermolysis Bullosum | AD or AR - COL7A1 (dystrophic)
KRT5 or KRT14 (simplex) |
Alpha-1-Antitrypsin | pulmonary emphysema (het and hom)
hepatic cirrhosis (hom) |
Alpha-1-Antitrypsin | Pi type-electropheretic mobility
-inhibitor of neutrophil elastase;
-M allele in 95% EA
alleles w/ dec prod or function; null mut only assoc w/ emphysema
-Z allele: glu to lys at 342 (10-15% Pi actx,impaired release from hepatocytes liver toxicity |
Alpha-1-Antitrypsin | treatment: no smoking, antioxidants (vit E), transplantation, alpha-1-AT augmentation |
Hirschsprung Disease | Congenital intestinal aganglionosis (80% rectosigmoid, 15-20% to sigmoid)
5:1 males to females |
Hirschsprung Disease | RET gene (AD LOF)
other genes(rare): GDNF, NRTN, EDNRB, EDN3, ECE1
12% occur as component of syndrome (some chromosomal, esp Down syn) |
Alagille syndrome | deficiency/atresia intrahepatic bile ducts;
cholestasis, neonatal juandice;
skeletal anomalies, ocular anomalies;
characteristic facial appearance |
Alagille syndrome | AGS1 - 94 % (JAG1 - ligand for Notch recptor)
AGS2 (NOTCH2) |
Criglar-Najjar syndrome | loss of bilirubin conjugation
UGT1A1 def
CN1 - bili 20-40 mg/dl
CN2 - bili 5-20 mg/dl |
Gilbert syndrome | reduced expression due to promoter polymorphism mild/intermittent hyperbili |
Duben Johnson syndrome | benign
MRP2/ABCC2 deficiency |
Progressive familial intrahepatic cholestasis | ATP8B1
ABCB11,
ABCB4 |
Hemochromatosis | excessive Fe absorption |
Fe overload in tissues causes | cirrhosis
diabetes mellitus
heart failure
more severe mainfestations in males |
Hemochromatosis | treat with phlebotomy
1 pt = 250 mg Fe |
Hemochromatosis | AR (1/400 caucasians)
carrier freq = 1/10
HFE gene in HLA complex
85% of mutations are C282Y (C282Y/C282Y, C282Y/H63D affected; H63D/H63D may be unaffected) |
Familial Hypercholesterolemia | def in LDL receptor
het (1:500) hypercholesterolemia, atherosclerosis;
hom: xanthomas, premature atherosclerosis |
Familial Hypercholesterolemia | treatment w/ diet, statins, other cholesterol lowering drugs |
Retinitis Pigmentosum | degeneration of photoreceptors or retinal pigment epithelium;
Night blindness, progress visual loss;
Abnormal ERG and visual fields |
Retinitis Pigmentosum | multiple genes/modes of inheritance
digenic inheritance |
Deafness | 50% prelingual deafness
30% of which nonsyndromic |
GJB2 | both AR and AD |
MYO7A | both AR (Usher) and AR/AD (Deafness) |
Autism-Spectrum Disorders | Deficits in social interactions, restricted interests/repetitive behaviors, language/communication |
Autism-Spectrum Disorders | Categories: autistic disorder, asperger syndrome (normal language), PDD-NOS |
Autism-Spectrum Disorders | Associated Features: regressive onset in 30%, szs 25%, dysmorphology 15-20%, microcephaly 5-15%, macrocephaly 30% |
Autism-Spectrum Disorders | genetic cause found 20-25%;
if cause unknown, sib risk 5-10% for ASD, 10-15% for milder abnormalities
i |
Autism spectrum disorders | cytogentically visible changes 5%;
15q11-q13 dup (mat der) 1-3%;
Trisomy 21 (7%)
45,X Turner syndrome
Deletions (2q37, 7q11.23 WS, 8q, 15q11 PWS, 22q13, Xp22.3) |
Autism spectrum disorders | CNV 7-10% |
| DD (lang > motor)
may be inherited from parent |
15q13.3 deletion | Intellectual disability
Epilepsy
CHRNA7 |
Autism spectrum disorders single gene | Fragile X; PTEN macrocephaly syn; Sotos; Rett; Tuberous sclerosis complex; metabolic disorders (mito, PKU, adenyloscuccinate lyase, creatine def dis, SLO) |
Psychiatric disorders | multifactorial, some candidate genes overlap between disorders, 22q11.2 del and schizophrenia, CNVs in families w/ psych disorders, pharmacogenetic considerations for tx. |
Cardiomyopathy | decrease in cardiac output; heart failure and arrhythmia; dilated vs hypertrophic |
Cardiomyopathy | mutations in contractile apparatus proteins; all modes of inheritance
genetic and nongen causes
infectious, storage disorders (hemochromatosis) |
Cardiomyopathy | treatment: ACE inhibitors, beta blockers |
Long QT | syncope, cardiac arrest, assoc w/ increase in sympathetic activity |
Long QT | treatment: beta-blockers, pacemakers, sympathetic ganlionectomy |
Long QT | Romano Ward (AD) - KVLQT1 (AR -JLNS w/ hl)
Other genes: HERG (K channel), SCN5A (Na channel), minK (K channel), MiRP1 (K channel) |
Hereditary Hemorrhagic Telangiectasia | Cutaneous and visceral AV malformations;
Epistaxis; GI bleeding; Pulmonary AVM- stroke and brain abscess |
Hereditary Hemorrhagic Telangiectasia | AD
genes: ENG, ACVRL1, SMAD4 |
Proteus syndrome | Progressive segmental overgrowth (skeleton, skin, adipose tissue, CNS) |
Proteus syndrome | AKT1 mosaic mutations in 90%;
c.49G>A (Glu17Lys);
sporadic |
Methyltransferase | addition of CH3 (methyl grp) to cytosine to give 5-methylcytosine |
Methylation marks erased in | germ cells |
Rett syndrome | developmental regression;
szs; loss of motor coordination; stereotypies |
Rett syndrome | XLD; MeCP2 loss of function mutations (methyl CpG binding protein 2) |
PWS | paternal deletion 70%;
maternal UDP 25-30%;
imprinting defect 1% |
AS | maternal deletion 68%;
paternal UDP 7%;
Imprinting defect 3%;
UBE3 mutation 11% |
Beckwith-Wiedemann syndrome | macrosomia, macroglossia, omphalocele, hemihyperplasia, dysmorphism, risk of tumors (hepatoblastoma, Wilm's tumor) |
Beckwith-Wiedmann syndrome | 85% sporadic, some AD, 1:13,000 births |
Beckwith-Wiedmann loci (normal) | IC1: IGF2 (paternal on), H19 (maternal on);
IC2: CDKN1C (maternal on), KCNQ1 (maternal on), OT1 (paternal on) |
Beckwith-Wiedmann syndrome (abnormal IC1 locus) | gain of methyl or microdel of maternal loci = (IG2 mat and pat on/ H19 mat and pat off);
5% of pts, 25% dev tumors, del assoc/ w 50% recurrence risk |
Beckwith-Wiedmann syndrome (abnormal IC2 locus) | loss of methylation (OT1 on in mat and pat, CDKN1C and KCNQ1 off in both mat and pat) - seen in monozyg twins and ART, 5% risk of tumor, usually sporadic |
Beckwith-Wiedmann syndrome (abnormal IC2 locus) | CDKN1C mutation in mat allele
(10% of patients, AD, low risk of tumors) |
Beckwith-Wiedmann syndrome (UPD) | Paternal 20% of cases, somatic mosaicism, hemihypertrophy, >25% risk of tumors |
Beckwith-Wiedmann syndrome (paternal 11p duplication) | 1% of cases
inc IGF2 and OT1 expression |
Russell-Silver syndrome | low birth weight; relative macrocephaly, FTT in infancy, delayed growth and bone age, skeletal asymmetry, urogenital anomalies, some with DD |
Russell-Silver syndrome | usually sporadic;
<5% maternal UPD7;
11p imprinting disorder;
same locus as BWS |
Russell-Silver syndrome | maternal UPD (rare)
maternal duplication (1-2% cases) |
Russell-Silver syndrome | hypomethylation of IC1 (no IG2 pat expression) 45%
hypomethylation of OT1 in maternal (no CDKN1C and KCNQ1 expression) (4% cases) |
Albright hereditary osteodystrophy | intellectual disability, subcutaneous calcification;
paternal transmission of GsAlpha mutation (GNAS gene) |
Pseudohypoparathyroidism-1a | AHO and resistance to multiple hormones;
maternal transmission of GsAlpha mutation (GNAS gene) |
Pseudohypoparathyroidism-1b | renal parathyroid resistance;
loss of maternal methylation at exon 1A (GNAS gene) |
Transient Neonatal Diabetes | IUGR, severe neonatal diabetes that regresses around 12 wks, may relapse at times of stress |
Transient Neonatal Diabetes | TNDM1 locus on 6q24: PLAGL1 and HYMA1;
Paternally expressed, maternal methylated:
UPD(6)pat 40%, Dup(6q24)pat 32%, mat hypometh TNDM1 28% |