sex chromosomes

It is a colloquial term used in parts of the Dominican Republic for children who are born appearing female with ambiguous external genitalia, but who naturally develop male sex organs and physical characteristics during puberty

guevedoces

Karyotype shows 47,XXX, Normal female phenotype, Height greater than average and greater than that of siblings, Slight delay in language and motor skills, Fertility unaffected

trisomy X

Karyotype shows 48,XXXX, Tall, with greatly reduced intellectual function

tetrasomy X

karyotype shows 49,XXXXX, Short stature, greatly reduced intellectual function, cleft palate, coarse facial features, hypotonia, microcephaly, hypertelorism, heart defects

pentasomy X

eyes are further apart, seen in pentasomy X for example

hypertelorism

Karyotype shows 47,XXY, Normal infant and childhood male phenotype, Caused by maternal and paternal nondisjunction associated with advanced parental aging

klinefelter

Women are more likely to have —- - presence of barr bodies in XX increases this

autoimmune disorders

Taller than average, Legs long relative to torso length, Low testosterone levels, High FSH levels, Loss of secondary sexual characteristics, Small testes and penis, Gynecomastia, Decreased libido, Azoospermia or oligospermia, Osteoporosis, Systemic lupus erythematosus, Thyroid disease, Diabetes, Lymphomas, Germ cell (in testes) tumors, IQ slightly lower than that of siblings, Delayed language and reading skills, §Delayed walking and motor skills, Higher incidence of autism spectrum disorders and ADHD

klinefelter

47, XYY, Paternal error in meiosis II, Only phenotypic feature is tall stature, Fertility unaffected; increased incidence of 47,XYY among offspring (sources vary), Severe teenage acne, slower motor and language development

jacob’s syndrome

45, X, Most common chromosome problem conceived, Most conceptions lost as early miscarriages (99%), Live-born infants thought to have undiagnosed mosaicism, Often diagnosed by prenatal ultrasound or at birth, Intellectual functioning same as general population, Short stature and decreased growth rate, No adolescent growth spurt, Average natural adult height of 47 inches, Pedal edema in newborns, Neck webbing, Kyphosis, scoliosis, Osteoporosis, §Hypertension (very common), Aortic malformations, Coronary artery disease, Hypothyroidism, Diabetes mellitus

turner syndrome

The most common genetic problem leading to reduced cognition among males, Involves silencing expression of FXMR1gene (which is responsible for brain development and maintenance of neuronal synapses), Silencing results from excessive trinucleotide repeat sequences (CGG) and methylation within the noncoding regions of the FXMR1 gene on the X chromosome

fragile X

for fragile X: The degree of expression is related to the number of repeat sequences—less than — usually has no expressed problems

50

fragile X: Women with 50 to 200 repeat sequences are —- who can transmit this change to their children in an X-linked-recessive manner, Problems occur when the number of repeat sequences increase by expansion - tends to increase with each succeeding generation,

premutation carriers

Transmitted by an unaffected grandfather  (normal transmitting male) to all his daughters, who are then premutation carriers, with disease expression in a grandson

fragile X

Autism spectrum disorders, Poor balance and coordination, Reduced cognition, Poor verbal skills, High anxiety, Attention deficit, Poor tolerance of change, Long, narrow face, Large ears, Prominent jaw, High, arched palate, Soft, smooth skin, Strabismus, Gastroesophageal reflux, Mitral valve prolapse, Large testicles (Macroorchidism) with increased volume, Recurrent middle ear infections, Flat feet, Delayed walking, Tremor (with aging)

fragile X

Occurs in some (~20%) premutation carriers, Onset of menopause before age 40

FXS associated primary ovarian insufficiency

Progressive ataxia and tremors after age 50, Usually occurs among people with 50 to 200 repeat sequences who do not express FXS

FXS associated tremor/ataxia syndrome

Some people have natural genotype of one gender and the phenotype of the other gender, known as——, This issue may not come to light until the person enters puberty and development does not proceed as expected

sex reversal

gene, located on the Y chromosome, encodes a protein that acts as the Testis-Determining Factor (TDF). It acts as a master genetic switch during embryonic development, initiating male testis formation and suppressing female reproductive pathways, with mutations potentially causing XY females (Swyer syndrome), normal Y chromosome > — produces TDF > testes form

SRY gene

testis secrete testosterone > stimulates the ——- to form male structures

mesonephric ducts

high levels of this cause regression of female (paramesonephric) ducts preventing female development in males, aka anti mullerian factor

AMF

Most often the difference between gender genotype and phenotype is related to embryonic tissue that is insensitive to normal hormonal influences or the hormones responsible for directing specific tissue development are not present, Both issues are genetic in origin

genotype-phenotype gender mismatch

XY genotype, female phenotype, Defective androgen receptor (AR gene on X chromosome), Testes form & secrete testosterone → but tissues can’t respond, Mesonephric ducts regress, partial female duct growth, Female external genitalia, no uterus/fallopian tubes, Blind-ending vagina, sparse body hair, Testes often intra-abdominal/inguinal; ↑ risk of cancer, Infertility, no menstruation.

androgen insensitivity syndrome

management of AIS:

gonadectomy, vaginal reconstruction

AIS is essentially:

XY females

SRY gene translocated to X chromosome → 46,XX+SRY, Without a full Y chromosome, SRY alone can direct testis & male structure development, •Male phenotype, often shorter stature, Infertile (no sperm), May have hypospadias, cryptorchidism, Similar to Klinefelter in infertility but usually normal intelligence & penile length

de la chapelle syndrome

de la chapelle syndrome is essentially:

XX males

Most abundant in tissues with high metabolic rates (muscle tissue), few genes, all coding for proteins needed to produce ATP, DNA is known as mtDNA

mitochondria

replicates separately from nuclear DNA and has few repair mechanisms

mtDNA

the presence of more than one type (normal/mutated) of mitochondrial DNA within a single cell, tissue, or body - the normal unaffected would be mitochondrial homoplasmy, linked to a range of conditions, including specific mitochondrial diseases, type 2 diabetes, cancer, aging, and neurodegenerative disorders

mitochondrial heteroplasmy

the vast majority of mitochondrial problems arise from mutations in —-

ova mitochondria

mitochondrial disorder: Tissue specific, Bilateral progressive vision loss, Expressed in early adulthood, looks like a blur hole in center of vision, stands for leber’s hereditary optic neuropathy

LHON

mitochondrial disorder: form of epilepsy, Affects many tissues, Expression begins in early childhood, Progresses to include ataxia, muscle weakness, dementia, hearing loss, blindness, and cardiomyopathy, aka myoclonic epilepsy with ragged red fibers

MERRF

mitochondrial disorder: affects many tissues and organs, Begins in middle childhood with recurrent headaches, generalized tonic-clonic seizures, muscle weakness, Progresses to intermittent one-sided paralysis and blindness, In adulthood, manifestations progress to impaired motor ability; reduced vision, hearing, cognition; diabetes mellitus, stands for mitochondrial encephalopathy, lactic acidosis, and stroke like episodes

MELAS

the most common sex chromosome abnormality conceived is —-

turners syndrome

individuals with an extra X or Y are usually —- than other family members

taller

early tissue that are capable of developing into anatomical male structures are ——, but both are present in XX and XY embryos

mesonephric ducts

early tissue that is capable of developing into anatomical female structures are —-

paramesonephric ducts

do not inherit fragile X from their affected fathers

males

the most common symptom associated with mitochondrial diseases is —-

fatigue

Nursing focus: monitor growth, puberty, cardiac/kidney health, and hormone therapy

turner syndrome

Nursing focus: testosterone therapy, psychosocial support, and diabetes screening

klinefelter

Nursing focus: early intervention, speech/occupational therapy, family genetic counseling, and school support

fragile X

Nursing focus: monitor for muscle weakness, fatigue, vision loss, cardiac and neurological changes

mitochondrial disease