Smith's Chromosome Syndromes

hypotonia with open mouth/protruding tongue, ID, characteristic features, brushfield spots, ear anomalies and hearing loss, short neck with excess skin, CHD (40%), abnormal genitalia and gonadal deficiency (some females have reproduced)

>50%: clenched hands (hypertonicity after neonatal period), rocker-bottom feet, short sternum, low-arch dermal ridge pattern on fingertips, feeble fetal activity, CHD, excess skin, single umbilical artery

• partial trisomy 18p: mild nonspecific phenotype
• partial trisomy 18q: clinically indistinguishable from full +18

>50%: midline defects (variable holoprosencephaly with clefting, cyclopia), ID, polydactyly, hearing defecgt, sloping forehead, low set ears, simian crease, heart defects, abnormal genitalia, single umbilical artery

mosaicism: variable degree of severity

ID, dysmorphic features incl. thick lips, deep-set eyes, prominent cupped ears, camptodactly, limited elbow supination, single palmar crease, major joint contractures, other anomalies

joint contractures, CHD, low-set malformed ears, severe ID, sloping forehead, micrognathia,

69% paternally derived due to dispermy

large placenta with hydatidiform changes, growth deficiency, syndactyly of 3rd and 4th fingers, CHD, brain anomalies

mixoploidy individuals show asymmetric skeletal growth and some degreee of psychomotor retardation

mental and growth retardation, ptosis, postaxial polydactyly, severe ID, microcephaly, dysmorphic features (long philtrum, micrognathia)

mental and growth retardation, broad nasal root, hypertrichosis, ID with brain anomalies, craniosynostosis, downturned corners of the mouth, anomalies of other organ systems

4p16.3

growth deficiency (prenatal onset), hypotonia, severe ID, greek-helmet facies (ocular hypertelorism with broad or beaked nose, microcephaly +/- cranial asymmetry, low-set simple ear with pits, caridac and genital anomalies

cat-like cry in infancy, microcephaly and round face, downward slanting palpebral fissures, growth deficiency, ID, simian crease, CHD

ID/DD, craniosynostosis-->trigonocephaly, upslanting palpebral fissures, hypoplastic supraorbital ridges

growth deficiency, severe ID, hypertelorism, delayed closure of anterior fontanelk distal phalangeal hypoplasia, skeletal anomalies

growth deficiency (prenatal onset), ID, hypotonia, microcephaly, dysmorphic features, camptodactyly

11p13 deletion

ID, ASD/ADHD, growth deficiency, aniridia, congenital cataracts, wilms tumor, obesity,

growth deficiency (prenatal onset), varying ID, dysmorphic features (hypertelorism, carp-shaped mouth), CHD

growth & mental deficiency, brain anomalies, dysmorphic features (high nasal bridge, eye defect, short-webbed neck), thumb hypoplasia

ID, dysmorphic features (prominent nose with broad nasal bridge), camptodactly, CHD, skeletal anomalies

mental and growth deficits, ptosis or epicanthal folds, prominent ears, wide-downturned mouth

disproportionate short stature, ID, hypotonia, midfacial hypoplasia with carp-shaped mouth, prominent antihelix, whorl digital pattern

triplication of 22q11

coloboma, hypertelorism, anal atresia, CHD, ear pits/tgs, mild ID

1:5000;

ID, lack of expressive language, microcephaly with large late-closing anterior fontanel, deep-set eyes, pointed chin, thickened ear helices, CHD, hypotonia, seizures, brachydactyly, camptodactyly

variable phenotype incl. hypotonia, ID, congenital diaphragmatic hernia, characteristic facies (coarse facies, hypertelorism, broad nasal tip, full tips), short limbs, CNS anomalies, CHD

growth retardation, ID, characteristic facies (round face, hypertelorism, prominent metopic ridge, thin upper lip, low-set malformed ears), tapered fingers, CNS anomalies

critical genes: HOXD cluster, DLX1/2

range of limb defects, ID, dysmorphic features, growth retardation, CNS anomalies, ocular anomalies, CHD, abnl genitalia

short stature, obesity, ID, sparse hair and arched eyebrows, dysmorphic features, small hands and feet with short 4th and 5th metacarpals

differential: Albright hereditary osteodystrophy

usually recurrent 1.6 Mb; critical genes: AK2 & DLG1 are homologues of X-linked MR genes PAK3 & DLG3

ID, microcephaly, mild dysmorphic features, risk for ASD or psychiatric conditions

EHMT1 haploinsufficiency

DD/ID, behavioral problems, CVN anomalies, characteristic facies (microcephaly, snophrys, downturned corners of mouth), +/- cardiac and genital anomalies

variable size; impt genes: CYP11A1 (genital anomalies?), SEMA7A, CPLX3, STRA6 (diaphagmatic hernia?)

ID, variable dysmorphic features, other variable phenotypic features (CHD, hearing loss, occular and genital anomalies, hands and foot anomalies)

recurrent

ID, expressive language disorder, single palmar crese, syndactyly, heart defects, ASD

recurrent; incl. KANSL1 haploinsufficiency

ID, speech delay, epilepsy, craniofacial anomalies in >50%, cryptorcidism in males +/- defects of other systems (skeletal, kidney, limbs, heart)

SHANK3 haploinsufficiency

ID, absent or delayed speech, hypotonia, ASD-like behaviors, dolichocephaly, prominet dysplastic ears, pointed chin

MECP2 & IRAK1 (interleukin receptor)

severe ID, absence or delayed speech, hypotonia, CNS anomalies, dysmorphic features, recurrent infections