22 Chromosome Trisomy 13 Syndrome
Patau syndrome
Microcephaly, scalp defects, microphthalmia, cleft lip/
palate, frequent holoprosencephaly, postaxial poly- dactyly, congenital heart defects, early death
Frequency: About 1 in 8,000 births.
Genetics
Trisomy 13: maternal age is a risk factor for aneu- ploidy; a minority of cases are due to a translocation trisomy.
Clinical Features
• Developmental retardation
• Holoprosencephaly
• Microcephaly, sloping forehead, posterior scalp lesions, frontal hemangiomas
• Hypotelorism, microphthalmia, iris coloboma, retinal dysplasia
• Cleft lip and palate
• Micrognathia
• Short neck, loose skin
• Low-set, dysplastic ears, deafness
• Cryptorchidism, abnormal scrotum
• Clenched hand, retroflexible thumbs, postaxial polydactyly, simian creases, narrow nails
• Prominent heel, polydactyly of toes
• Congenital heart defects
• Inguinal and umbilical hernia
• Severe mental deficiency, seizures, hypotonia Differential Diagnosis
• Other chromosome imbalances, notably trisomy 18 syndrome
Radiographic Features Skull
• Moderate microcephaly, sloping forehead
• Wide sagittal sutures and fontanels
• Hypotelorism, occasionally cyclopia
• Shallow supraorbital ridges
• Facial clefts
• Micrognathia Chest
• Thin posterior ribs
• Cervical rib, anomalies of rib number
Fig. 22.1. Patient 1, newborn. Microphthalmia, hypotelorism, and premaxillary agenesis
Fig. 22.2. Patient 2, 6 months. Microphthalmia, depressed forehead owing to wide open metopic suture, short upturned nose, micrognathia, low-set ears, short neck with redundant skin
Spine
• Increased interpediculate distance
• Abnormal vertebral bodies Pelvis
• Hypoplasia of pelvis
• Shallow acetabular angle
Extremities
• Postaxial polydactyly, syndactyly
• Fifth finger clinodactyly
• Thin, dysmorphic, absent phalanges
• Talipes equinovarus
• Prominent heel
• Dorsiflexed, short, bifid hallux
• Absent phalanges of toes
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Fig. 22.3 a–d. Variable degrees of microcephaly, wide open fontanels and cranial sutures, cleft palate, and micrognathia in apatient 3 (newborn), b patient 4 (newborn), c patient 5 (new-
born), and d patient 6 (newborn). Striking hypotelorism is also seen in patients 3 (a) and 4 (b)
a
b
d c
a
b Fig. 22.4. a Patient 6, newborn; b patient 7, newborn. Note anomalies of rib number, increased interpediculate distance, enlarged heart shadow, and large umbilical hernia (b)
Fig. 22.5. Patient 8, newborn. Note small, flaring ilia, and shallow acetabular angle
Bibliography
Daugaard-Jensen J, Nodal M, Kjaer I. Pattern of agenesis in the primary dentition: a radiographic study of 193 cases. Int J Paediatr Dent 1997; 7: 3–7
De Grouchy J, Turleau C. Clinical atlas of human chromo- somes. Wiley, New York, 1977
Delatycki M, Gardner RJ. Three cases of trisomy 13 mosaicism and a review of the literature. Clin Genet 1997; 51: 403–7 Hodes ME, Cole J, Palmer CG, Reed T. Clinical experience with
trisomies 18 and 13. J Med Genet 1978; 15: 48–60
Schinzel A, Hayashi K, Schmid W. Further delineation of the clinical picture of trisomy for the distal segment of chro- mosome 13. Hum Genet 1976; 32: 1–12
Taylor AI. Autosomal trisomy syndromes: a detailed study of 27 cases of Edwards’ syndrome and 27 cases of Patau’s syn- drome. J Med Genet 1968; 5: 227–52
Taylor M, Juberg R, Jones B, Johnson W. Chromosomal vari- ability in the D1 trisomy syndrome. Am J Dis Child 1970;
120: 374–81
Zoll B, Wolf J, Lensing-Hebben D, Pruggmayer M, Thorpe B.
Trisomy 13 (Patau syndrome) with an 11-year survival. Clin Genet 1993; 43: 46–50
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Fig. 22.6. Patient 9, newborn. There are bilateral clubfeet, and hip and knee dislocation at the right side, with unossified epiphyses at knee
Fig. 22.7 a–d. Postaxial hexadac- tyly of varying shape and degree in a, b patient 8 (newborn), c pa- tient 6 (newborn), and d patient 10 (newborn)
a
b
d c
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Fig. 22.8. a Patient 4, newborn:
absent or severely hypoplastic middle toe phalanges, and short proximal and distal phalanges.
bPatient 3, newborn: bifid distal phalanx of the great toe, absent phalanges, irregular metatarsals, and irregularly ossified calcaneus
a
b
