chromosomal region

20p - proximal

symptoms

case no. 

gender

age at diagnosis

studied 
material

de novo/ 
inherited

GTG-banding result
grade of mosaicism

final FISH result of the sSMC

FISH
methods

UPD
result

clinical symptoms

reference

see below

healthy child born, normal after 3 months

see below

Normal female; sSMC detected due to child with mild developmental delay; patient rolled at 7 months of age, crawled at 11 months of age, and pulled to stand and cruised at 12 months of age; patient has a two word vocabulary at 12 months of age; developed seizures at 10 months of age; mild dysmorphic features; normal head MRI. The patient’s mother, two siblings, and maternal grandfather carry the marker in a mosaic state. All family members are phenotypically normal.

47 chromosomes: mar1: min(20)(:20p11.21→20q11.21:)[5]/
mar2:min(20)(:20p11.1→20q11.21:)[1]/
mar3:r(20)(::20p11.1→20q11.21::)[1]/
mar4:r(20)(::20p11.1→20q11.21::20p11.1→20q11.21::)[5]/
mar5:min(20)(:20p11.1→20q11.21::20p11.21→20p11.1:)[7]/
mar6:invdup(20)(:20p11.1→20p11.21::20q11.21→20p11.1: :20p11.1→20q11.21::20p11.21→20p11.1:)[1]/ mar7:invdup(20)(:20q11.1→20q11.21::20p11.21→20q11.1: :20q11.1→20p11.21:)[1]/
mar8:invdup(20)(:20q11.1→20q11.21: :20p11.21→20q11.1::20q11.1→20p11.1:)[1] 
48 chromosomes: mar9:min(20)(:20q11.1→20p11.21::20q11.21→20q11.1:) plus mar4:r(20)(::20p11.1→20q11.21::20p11.1→20q11.21::)[1]
FISH-data: RP11-96L6 in (25.47MB) and  RP11-243J16 in (29.93MB) on sSMC

D20S473,  D20S470,  D20S478, D20GATA46C01,  D20S471, D20S484, D20S486 

At birth, patient appears normal (marker detected on amniocentesis for increased Down syndrome risk on serum screen); normal development at 9 months of age.

Amniocentesis due to advanced  maternal age; child born without any signs or symptoms apart from a isolated syndactyly, type I of toes 2 and 3. At age of 20 months boy normal

normal female, primary amenorrhea

case no. 

gender

age at diagnosis

studied 
material

de novo/ 
inherited

GTG-banding result
grade of mosaicism

final FISH result of the sSMC

FISH
methods

UPD
result

clinical symptoms

reference

case no. 

gender

age at diagnosis

studied 
material

de novo/ 
inherited

GTG-banding result
grade of mosaicism

final FISH result of the sSMC

FISH
methods

UPD
result

clinical symptoms

reference

Uncomplicated pregnancy; weight: 4250g, length: 52cm; umbilical hernia one unilateral hydrocele and restricted mobility of hips; at 8m developmental delay and dysmorphic features like full cheeks, deep-set eyes, slight upslanting palpebral fissures, convergent strabismus of left eye; lipoma at base of nose at age of 14m; mild micrognathia, broad neck and thorax, diastasis recti, clinodactyly of 5th fingers; walking at 23m; 

see below

micrognathia, microcephaly, intrauterine growth retardation; pregnancy terminated

see below

born at 36 weeks gestation; birth weight - 1.92kg; at birth - plagiocephaly; micrognathia; long philtrum; high arched palate; low set ears; slightly widened bulbar fingers; slightly prominent occiput and prominent forehead; right inguinal hernia; inverted nipples; hypospadias; torticollis; a heart scan at 3m showed 4 VSDs and a PFO. He also suffers from gastroesophagial reflux; mild optic nerve hypoplasia, nystagmus and some asymmetric opsoclonus - more in the left eye than right eye. MRI brain scan in at 10m of age revealed a wide range of craniocerebral abnormalities, neurodevelopment delay; dysplastic inner ear on left side and cerebellar tonsillar ectopia through the foramen magnum. At 1y he was operated on to lower his left un-descended testicle. Spine MRI and X-rays at 13m showed scoliosis. At 16m still unable to sit unaided and now had gaiters for his legs. Feeding problems after birth and was fed via an NG tube until 1y when a gastrosomy PEG was introduced. At 15m weight 7.22kg.

ultrasound abnormalities, TOP

congenital heart disease and minor anomalies at birth; At 3.1y child showed appearance reminiscent of dup(20p) syndrome; patient died at 5y of unknown reasons

born during pregnancy week 38 with growth retardation, weight 1,940 g, length 45 cm; marked feeding problems, poor weight gain, no malformations other than a small ASD. At 30 m she developed normally, but she was still very small and had feeding difficulties.

Amniocentesis due to intrauterine growth retardation (week 22); TOP at 34 weeks; weight was 1,630 g (5th centile), height 43 cm (10th centile), and occipitofrontal circumference (OFC) 27.5 cm (<5th centile). Moderate craniofacial dysmorphism, including elongated skull with a shelf, a broad nose, a bilateral crease below the lower eyelids, microretrognatia, normally implanted but abnormal ears, and a slight nuchal edema. Hands, feet, and genitalia were normal. Internal examination showed no anomaly. Skeletal X-rays were normal.

Developmental delay, lipoma of the corpus callosum, hypotonia, VSD, ASDII

Born after uneventful pregnancy, 38th week of gestation (2850g weight). Long bones were reported as shortened at birth; suggestion of hypochondroplasia, parents also small (~160cm).
At 4y: height: 91.8cm (<3 centile), Weight: 15.4 kg (10.-25. centile). Breathing through mouth, speech is slurred, and poor in vocabulary. Macrocephaly, slightly reclined neck, short long bones, strong suborbital skin fold, flat nasal root. Intelligence borderline (60-70).

Developmental delay and facial dysmorphism. Hypotelorism and macrocephaly

congenital malformations, born at term, heart defect suspected, weight 4010g, length 52cm, at 8y mild motor development delay, muscular hypertonia, dystonia; at 7 years: weight 26 kg, length 127cm, OFC=55cm, macrocephaly (borderline), dolichocephaly, prognathia, large alveolar ridge, brain: dilated lateral ventricles (moderate), low-set dysplastic ears, epicanthus, short wide nose, short philtrum, arched palate; small umbilical hernia, polythelia, short neck, speech dysarthria

Psychomotor delay

Amniocentesis due to a Turner syndrome in previous pregnancy; normal sonography; TOP in week 24; postmortem examination: weight 670g (50th centile); length 32 cm (25th centile); OFC 22.5cm (50t centile), dysmorphism: high forehead with frontal bossing, voluminous ocular globes, hypertelorism, low set ears with hypoplastic helix, wide flat nasal bridge, long smooth philtrum, thin upper lip, microretrognatia, hypoplastic labia and clitoris, rocker bottom feet;

min(20)(:p11.1→q11.1:) {cenM}
47,XX,+min(20)(:p11.1→q11.22:)[18]/
47,XX,+min(20)(:q11.22→p11.1::p11.1→q11.22:)[7]/
47,XX,+r(20)(::p11.1→q11.22::p11.1→q11.22::)[3]/
46,XX[2] {subcenM}

microsatellites tested for UPD : D20S113; D20S199; D20S189; 1H5, D20S41; UT246; D20S98; D20S104; D20S114; D20S184; D20S17; D20S119; D20S59; D20S195; D20S173; D20S64
growth retardation; minor facial dysmorphic features; hyperactive;  mother at age of conception 40y; intra-uterine growth retardation; 

Female studied due to primary amenorrhea, hirsutism, mild mental retardation; myopic retinal degeneration, horizontal nystagmus, no uterus and abnormal  ostium of urethra in the bladder.

see below

Birth weight: 3510g, length: 48cm; mental retardation, behavioral problems, low-set ears, and restricted mobility in the hips.

case no. 

gender

age at diagnosis

studied 
material

de novo/ 
inherited

GTG-banding result
grade of mosaicism incl. final FISH result of the sSMC

FISH
methods

UPD
result

clinical symptoms

reference

n.a.

Sotos syndrome (cerebral gigantism)

n.a.

Alagille syndrome (arteriohepatic dysplasia, AHD) without liver involvement

2m

facial dysmorphism = prominent metopic suture, epicanthic fold, peripalpebral edema, small and thick ears, prominent cheeks; walking with 25m, speech delay; at 3y no growth abnormalities. 

16m

psychomotor retardation, craniofacial anomalies and severe vision deficit. 

case no. 

gender

age at diagnosis

studied 
material

de novo/ 
inherited

GTG-banding result
grade of mosaicism

final FISH result of the sSMC

FISH
methods

UPD
result

clinical symptoms

reference

2y

dysmorphic features like scaphocephaly, high pitched voice, high palate, clinodactyly of fingers 2, 4 and 5 towards the 3rd finger, short stature; 

2y 8m

Normal pregnancy, born in 39th week, weight, length and OFC normal, APGAR 9/9/-;  at 2y8m psychomotor retardation, facial abnormalities, brachyturricephaly, normal set ears with lobe crease, high arched palate, short neck, bilateral clinodactyly of 5th finger; both testes in inguinal canal.

CVS due to advanced  maternal age;  born at 35 weeks' gestation following preterm prenatal. rupture of membranes. APGAR score 2/6/8; Birth weight 1730 g  (10. percentile) length 44.5 cm; Noted at birth: asymmetric, triangular face; prominent forehead; bulbous nose with slightly upturned tip; hypoplastic and short philtrum; small mouth; high palate; micrognathia; retrognathia; large, flat, and simple ears; redundant skin on neck, chin, and upper shoulders; blind shallow sacral dimple; proximally placed thumbs which folded over the palms; clinodactyly of the second, fourth, and fifth fingers; feet held in eversion, prominent heels; wide space between the first and second toes; proximally placed fifth toes; hypotonia; increased skin elasticity; and hyperextensible joints.
At 34 m: failure to thrive, dysfunctional swallowing, and generalized hypotonia; gross motor development delayed, but fine motor coordination, expressive language, and problem solving were appropriate for age. On follow-up at 13 months, the patient's weight was 6730 g (5. percentile) and height was 68'5 cm (5. percentile); percutaneous gastrostomy tube for feeding. At 16 m, weight 8230 g (3. percentile); height 70,8 cm (3. percentile) still required gastrostomy tube feedings.

Global delayed development in gross motor, fine motor, speech and social skills, height and weight below 3rd centile, heart defect, hypertelorism, depressed root of nose, low-set ears, bilateral plantar furrow (1, 2), clubbed fingers

At 14 m developmental delay and some dysmorphic features. Born at 39 weeks gestation after uncomplicated pregnancy; at birth small and broad hands and feet as well as low set ears were noted. At 14 months coarse round facies, full cheeks, slight upslanted palpebral fissures, convergent strabismus, micrognathia, high and narrow palate, low set ears, brachycephaly, broad neck and chest, pectus excavatum, widely spaced nipples and normal external genitalia. He had broad and short hands and feet, brachydacyly of fingers and toes, as well as 2nd/3rd syndactyly and clinodactyly of 5th fingers. Neurological examination normal. Developmental delay with poor social contact. Radiologic studies confirmed brachycephaly, short hands showing coarse metacarpal bones, slight platyspondyly and mild generalized osteoporosis.
The mother had a borderline IQ, a coarse facies with upslanting palpebral fissures and broad nose with hypoplastic nares. She had a short neck, asymmetric thorax with rib retraction and hypoplasia on the left side, with lowering of left shoulder. There was a slight pectus excavatum and hypoplasia of the pectorals muscle. The radiological studies confirmed the described skeletal anomalies, as well as platyspondyly. The father was normal.

prenatal

Advanced maternal age; positive maternal marker serum screen; child born and at 1y developmental delay and dysmorphic features

prenatal

2y

case no. 

gender

age at diagnosis

studied 
material

de novo/ 
inherited

GTG-banding result
grade of mosaicism

final FISH result of the sSMC

FISH
methods

UPD
result

clinical symptoms

reference

Normal pregnancy; born at term by cesarean section due to failure to progress. The parents reported: always delayed in all areas: first walked at 2y, at 4y vocabulary of about 20 words. At 12y able to bath herself, make her bed and wash dishes; was in special classes; behavioral evaluation concluded that she had pervasive developmental delay with mild to moderate autism. MRI showed decreased brain volume on the left; an NMRI of the spine revealed extrusion of the L3–4 as well as a bulge at the L5 level. An MRI of the abdomen demonstrated a right atretic kidney. The parents reported episodes of sleep apnea at night and a sleep study did reveal short episodes of central sleep apnea, with an average duration of 12 s and no desaturations. Physical exam: height 125.4 cm (<5%); weight 38.8 kg (25%); head circumference 50 cm (10%); down-slanting palpebral features with right-sided facial microsomia, right ear slightly over-folded.

47,XX,+mar[?%]/
46,XX[?%]

r(20)(::p13→q13.32::)[7]/
 r(20)(::p13→q13.32::p13→q13.32::) [1]

advanced maternal age; TOP

47,XY,+mar[100%]

mar(20)

advanced maternal age; TOP

47,XY,+mar[20]/
46,XY[3]

r(20)(::q11.21→q13.12::)

advanced maternal age; Half of twin with the other fetus being carrier of a mar(20)(investigated elsewhere)

case no. 

gender

age at diagnosis

studied 
material

de novo/ 
inherited

GTG-banding result
grade of mosaicism

final FISH result of the sSMC

FISH
methods

UPD
result

clinical symptoms

reference

3y

postnatal: congenital heart disease (VSD), minor anomalies; pulmonary atresia; at 3.1 y mild brachycephaly; height and weight an 90-97th centile; OFC on 75th centile; epicanthic folds, long philtrum, both hands slightly stubby; clinodactyly of 5th finger; mild developmental delay; died at 5y for unclear reasons.

case no. 

gender

age at diagnosis

studied 
material

de novo/ 
inherited

GTG-banding result
grade of mosaicism incl. final FISH result

FISH
methods

UPD
result

clinical symptoms

reference

{40}

{38-39}

13m

At birth 3,000 g (full term pregnancy); generalized tonic seizures at ages 1, 3, and 13 months that were controlled with Phenobarbital. Discrete facial dysmorphism with large forehead, mild hypertelorism, long prominent nose, short upper lip, and dysplastic ears but no trigonocephaly or microcephaly; anterior anal placement and asymmetric thigh folds, mild ataxia, psychomotor development delay.

{41}