Overgrowth Flashcards
Patterns of overgrowth can fall into what 4 major categories?
- tall stature
- obesity
- macrosomia (all growth parameters elev)
- regional overgrowth
Genetic obesity is most likely found as early onset obesity, at what age and why?
< 5y
> 95% BMI
- this is an age where you are growing a ton and still have restrictions on food access
With low tone, you also have low _____ ?
metabolic rate
When we have adequate amounts of fat stores, then we produce ___? which travels where? to do what?
leptin –> travels to the hypothalamus and stimulates leptin receptor ___> stimualtes POMC neurons to produce hormones to travel through body
ends w dec food intake + inc resting met rate
What is the inheritance pattern for MC4R deficiency?
semi-dominant disorder –> partial phenotype w 1 copy + severe pheno w both
AR form is rare
What are clinical features of MC4R deficiency?
(semi-dom + rare AR)
Dom: hyperphagia, extreme obesity, early onset
AR: hyperphagia, binge
2-5% total early onset obesity = due to?
MC4R deficiency
What is the inheritance pattern for Leptin Def?
AD
AR
What are clinical features of Leptin Def?
AD: hyperphagia + early onset obesity
AR: freq infections, hypogonadotropic hypogonadism, hypothyroidism
What are treatment options for Leptin Def?
leptin replacement
What is more common: Leptin Def OR Leptin receptor def?
Leptin Receptor Def, which is sad bc this one does not have treatment option and accoutns for 3% cases of severe obesity
What does POMC deficiency stand for?
pro-opio-melano-cortin
melano –> melanin that provides dark pigmentation; classic pt = pale ging
cortin –> cortisol bc POMC stsim the ATCH-cortisol pathway
POMC deficiency involves ____ insufficiency and why?
adrenal bc the POMC is supposed to stim the ACTH-cortisol pathway and cannot bc deficiency
What is PSCK1 deficiency?
(AR)
So PSCK1 –> processes propeptide hormones into mature form
so when def, leads to malabsorptive diarrhea, low blood sugar after eating, obesity
(so can think abotu if not abs fatsin the intest, then it is like osmotic pull for water –> diarrhea)
What are the disorders that are assoc w macrosomia?
NOn-Gen:
- infant of diab mom
Gen:
- BWS
- Sotos
- NFIX related disorders
- Weaver
- PTEN-hamartoma syndrome
- Simpson Golabi Behmel
- Gorlin
- Perlman
Why does infant of diabeteic mother have BW > 4kg usually?
they have long exposure to sugar during preg, so then fetus resp by inc insulin levels
they end up storing the extra sugar
What are som symp of infant of diab mom in MILD cases?
- low BS (bc high levels circ insulin)
- prolonged jaundice, high blood counts
- septal hypertrophy of heart
good prognosis, can usu come off IV pretty quick
What are som symp of infant of diab mom in SEVERE cases?
- holoprosencephaly
- caudal regression syndrome –> sacrum + legs def in devel
- proximal femoral deficiency –> hips + femur not dev well
What are the classic findings in BWS?
- fetal overgrowth
- omphalocele
- internal organ overgroth
- hemihyperplasia
- macroglossia
- proptosis
- risk of Wilms tumor + hepatoblastoma
- prolonged hypoglycemia (pancreatic necidioblastosis - so they are not releasing insulin the way they should)
What are outcomes like for BWS?
- usu pretty good as long as there is not severe hypoglycemia)
How often do you screen for cancer risks in BWS?
so Wilms tumor + hepatoblastoma
(think about hwo overgrowth syn have high turnover rate of cells –> inc cancer risk)
every 3 months
hard bc hepatoblastoma NOT have clear treament
What are screening guidelines outside of cancer screens for BWS?
- AFP every 3 months for 1st 4y
- renal US every 3 mo until 8y (then annual until mid-adoles)
What is Sotos syndrome caused by?
90% caused by LOF from NSD1 (gene regulator)
(usu see changes at seq level)
What are classic findings in Sotos syndrome?
(NSD1)
- inc birthweight (and ht cont even if wt does not)
- adv bone age (bones mature faster than they should)
- large, narrow head
- bossing of forehead
- receding hairline
- elongated chin
