EP11.12: Antenatal diagnosis of Miller‐McKusick‐Malvaux (3‐M) syndrome: a case report

Abstract

The Miller-McKusick-Malvaux (3-M) syndrome is a rare primordial growth disorder characterised by low birth weight, reduced birth length, severe postnatal growth restriction, and a spectrum of minor anomalies, including facial dysmorphism. Although individuals with 3-M syndrome have short stature, and skeletal abnormalities, their intelligence is not affected. 3-M syndrome is inherited in autosomal recessive manner, and to date, there are only about 100 cases of affected individuals that have been identified worldwide. In the antenatal period, individuals with 3-M syndrome typically have long bones which are below the 3rd centile, and they are generally small for gestational age. This slow growth continues throughout childhood and adolescence. They have low birth weight and length, and remain much smaller than others in their family, growing to an adult height of approximately 120-130 cm. The majority of 3-M cases are diagnosed postnatally. We present a case of 3-M syndrome which was diagnosed during the antenatal period. This is the first 3-M case diagnosed prenatally which led to a live birth. Due to the fact that 3-M syndrome is inherited via an autosomal recessive pattern, early diagnosis in a fetus can aid in the genetic counselling for the current and future pregnancies. Antenatal detection is possible by analysis of DNA extracted from fetal cells by chorionic villus sampling or amniocentesis but in the absence of a family history, prenatal diagnosis is often difficult, and 3-M joins a long list of possible causes of shortened long bones, such as include Silver–Russell syndrome, Bloom syndrome, Dubowitz syndrome, Rubistein-Taybi syndrome, Floating-Harbor syndrome, Mulibrey nanism and fetal alcohol syndrome. 3-M syndrome is a rare genetic disorder that should be considered in the differential diagnoses when assessing fetuses which present with intrauterine growth restriction and short long bones. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.