Repeating Familial Fetal Cystic Hygroma with Normal Karyotype

Headnote

Keywords: Cystic hygroma, familial, hydrops fetalis, recurrent

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Cystic hygromas are the consequences of anomalies of the lymphatic system and are mostly related with chromosomal abnormalities.

Turner syndrome, trisomy 21, trisomy 18, and trisomy 13 are the most frequently detected chromosomal abnormalities related with cystic hygromas. Regardless of gestational age aneuploidy is the most likely cause of prenatally diagnosed cystic hygromas.

Recurrence of fetal cystic hygroma in subsequent pregnancies is extremely rare. A few reports have suggested existence of an autosomal recessive trait of cystic hygroma.

A 32 year old gravida 10 para 1 with no parental consanguinity was ini - tially seen at 12th week of gestation. She had eight abortuses with two of them were diagnosed with cystic hygroma each ended with fetal demise at 12th and 16th weeks of gestation respectively. One the fetuses underwent autopsy and chromosomal analysis. That fetus was a 46, XY with normal anatomical structure. In her latter pregnancy a cystic hygroma of 20 mm was detected at 12 weeks of gestation and chorion villus sampling was performed at the same visit. The chromosomal constitution of the fetus and both of the parents were normal. Indirect Coombs toxoplasmosis, rubella, cytomegalovirus, and parvovirus tests were negative. Termination of pregnancy was suggested but the patient decided to continue pregnancy. Fetal hydrops fetalis developed at 19 weeks of gestation and pregnancy was terminated but autopsy was not performed.

This case supports that cystic hygroma, associated with a normal karyotype, can be inherited by a Mendelian autosomal recessive pattern.

Familial recurrence of cystic hygromas can be a result of a variety of genetic mechanisms as autosomal dominant with variable expression, germline mosaicism or autosomal recessive. The presence of affected female and male fetuses with unaffected siblings rules out an X-linked inheritance. An autosomal recessive inheritance pattern could be the mechanism since there are several cases reported in consanguineous families. Cystic hygromas are usually lethal in recurrent familial cases compared to euploid sporadic cases. Most of the fetuses with cystic hygromas have abnormal karyotype and recurrences are rare and but a patient with a history of cystic hygroma with normal karyotype must be counselled about the increased risk of recurrence in following pregnancies.