Genetic Syndromes

aka Patau
path:
- In most cases all or a majority of the extra 13 chromosome is present. Translocation can be a cause, thus imparting 10% risk of recurrence and the need for parental testing.
- defect in the fusion of the prechordal mesoderm, an integral embryological structure affecting growth of the midface, eyes, and forebrain.
Risks
- Advanced maternal age is commonly noted
Symptoms
- Precordal mesoderm fusion result in catastrophic midline defects, including holoprosencephaly, microcephaly, microphthalmia (small eyes), cleft lip/palate, and omphalocele. Abnormal brain development results in intellectual disability and seizures. Additional abnormalities include polydactyly and cutis aplasia (focal skin defect of the scalp).
- complex heart lesion including atrial septal defect (ASD), ventricular septal defect (VSD), and dextrocardia.
- rocker bottom feet.,

Angelman

Aka “happy puppet syndrome” In most case
path: it is caused by an interstitial deletion of chromosome 15q1-q13; the deleted material always comes from the maternal side (the same deleted segment from the paternal side results in Prader-Willi).
symptoms
- unusual gait and the unprovoked outbursts of laughter.
- large mouth with tongue protrusion, hypopigmentation with blond hair and pale blue eyes.,

path: Deletion of the short arm of chromosome 5 is the etiology.
symptoms:
- microcephalic, has a rounded face, hypertelorism, and epicanthal folds
- The distinctive, catlike cry is likely caused by abnormal laryngeal development; it tends to resolve with time. Profound mental retardation, self-injury behavior, hypersensitivity to sound, and repetitive behaviors are commonly seen. About 85% of cases are paternal in origin.,

symptoms: Features include bushy eyebrows, hirsutism, limb defects, VSD, and mental retardation.,

Last updated 5 years ago