Acrocephalosyndactyly

Acrocephalosyndactyly
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Description

Acrocephalosyndactyly is also known as Apert syndrome, and is one of the craniosynostosis syndromes. It is inherited in autosomal dominant fashion, although the vast majority of cases represent fresh mutations.

Diagnosis

Length and weight tend to be increased at birth, with head circumference in the normal range. Linear growth gradually decreases during childhood, so that adults are usually well below average in height. Skull shape is distinctive, with brachycephaly, flat occiput and full forehead. There is irregular craniosynostosis, particularly of the coronal suture, and the fontanelles are usually very large and delayed in closure. There is midfacial hypoplasia, with resultant relative mandibular prognathism. The orbits are shallow, and there is hypertelorism and downward slanting of the palpebral fissures. Cleft soft palate or bifid uvula occurs in about one third of cases. There is osseous and/or cutaneous syndactyly involving both upper and lower limbs, and varying from partial to total fusion. There may be brachydactyly, and the distal phalanges of the thumb and hallux may be broad and valgus. Occasional associated skeletal anomalies include radio-ulnar synostosis, short humerus and limitation of joint mobility. Other visceral abnormalities include ventricular septal defect, renal cysts, hydronephrosis and tracheal anomalies.

Differential Diagnosis

Saethre-Chotzen syndrome (acrocephalosyndactyly type III) is characterised by usually mild coronal craniosynostosis and facial anomalies as well as cutaneous syndactyly of the hands and feet. The facial appearance typically shows dystopia canthorum (wide spacing between the inner canthi), low frontal hairline, ptosis, deviated nasal septum and flattened midface – very different to the usual facies of Crouzon syndrome. In Antley-Bixler syndrome there is significant humero-radial synostosis resulting in fixed flexion of the elbow as well as femoral bowing and craniosynostosis involving not only the coronal but the lambdoid sutures.

Sonographic Features

Brachycephaly Osseous syndactyly – ‘mitten hands”

Brachydactyly Minimal independent digital movement

Decreased fetal movement

Associated visceral anomalies

VSD 

Renal cyst 

Hydronephrosis 

Oesophageal stenosis/atresia

Associated Syndromes

References

  1. Chenoweth-Mitchell C, Cohen GRPrenatal sonographic findings of Apert syndromeJ Clin Ultrasound 22:510-514
  2. Parent P, Le Guern H, Munck MR, Thoma MApert syndrome, an antenatal ultrasound detected caseGenet Counselling 5:297-301
  3. Pelz L, Unger K, Radke MEsophageal stenosis in acrocephalosyndactyly (Letter )Am J Med Genet 53:91
  4. Cohen MM Jr, Kreiborg S Visceral anomalies in the Apert syndrome Am J Med Genet 45:758-760
  5. Robinson LK, et al Prenatal diagnosis of the Apert syndrome Ninth Annual David W Smith Workshop on Malformations and Morphogenesis
  6. Narayan H, Scott IVPrenatal ultrasound diagnosis of Apert’s syndromePrenat Diagn 10:187-192
    Hill LM, Thomas ML, Peterson CSThe ultrasound detection of Apert syndrome J Ultrasound Med 6:601-604
  7. Leonard CO, Daikoku NH, Winn KPrenatal fetoscopic diagnosis of the Apert syndromeAm J Med Genet 11:5-9