Paediatric Genetics Flashcards
Describe Down’s syndrome
Trisomy 21
Learning disability, congenital heart disease, hypothyroidism, immunity, and early onset Alzheimer’s disease
How is a rare intellectual disability/ malformation syndrome?
History, description, recognition of patterns and testing - standard (biochemical and chromosome structure), targeted testing and moving to trio-based exome/ genome
What is looked for in the head of a dysmorphic child?
Shape, size and ear position - low set, posteriorly rotated and not as crinkly (indicates lack of maturity)
What are common eye abnormalities that are looked for?
Hypertelorism - inner canthal distance TCD and inter-pupillary distance IPD are increased
Telecanthus/ epicanthic folds - ICD and IDP increased
What are hand measurements which are done?
Finger length, digital abnormalities and palmar creases
Ex. Marfan syndrome and Down’s syndrome
What are finger descriptions used?
Arachnodactyly - long and skinny fingers
Brachydactyly - short and fat fingers
What is malformation?
Alone or as part of a syndrome
Ex. polysyndactyly alone (Hox D13) or acrocephalo-polysyndactyly (Greig/ GL13)
What are the features in Grieg’s syndrome?
Tall forehead, polydactyly and syndactyly
Inherited - dominant
What is a sequence?
One abnormality leads to another, can have multiple causes
Pierre-Robin sequence - small chin to cleft palate
Foetal akinesia sequence starting with reduced foetal movement - reduce breathing, cleft and contractures
What is deformation and disruption?
Pattern of development normal to start with but becomes abnormal
Deformation - organ parts are there
Disruption - parts of organ/ body part absent
Eg. amniotic bands
Describe association
Two features or more features occur together more often than expected by chance
Mechanism unclear
Ex. VATER
What does VATER stand for?
Vertebral/ VSD
Ano-rectal atresia
Tracheo-
oEsophageal fistula
Radial anomalies
What is a syndrome?
Distinct group of symptoms and signs, associated together, form a characteristic clinical picture or entity
Describe the features of Turner’s syndrome
45X
Lymphoedema, increased carrying angle, low hairline, wide spaced nipples, sandal gap, short stature, coarctation of aorta, hypothyroidism, primary amenorrhoea, infertility and hypertension
What is the investigations for malformation syndromes?
Microarray, fragile X, targeted tests driven by phenotype and trio-based exome/ genome analysis
Describe the features of 22q11 deletion
Cleft palate, abnormal facies, thymic hypoplasia/ immune deficiency, calcium and heart problems
CATCH22
What is Glut1 deficiency?
SLC2A deletion or mutation
Treatment with ketogenic diet
Describe the importance of phenotyping
Key to assessment of clinical relevance is the phenotype
Accurate description of clinical feature is important
Help families with future pregnancies, clinical care and treatment
